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MG MGA - Getting The Temperature Up
| We seems to be getting side tracked from Salt On the UK Roads so I have started a new thread to carry on with with my low engine running temperatures. To summarise where we are at: "My engines have always always run coolish, the old 1500 and the 1800. Variety of thermostats used and tested and all work ok. Open at correct temperatures. Gauge comes off the stop when I would expect it to, but always settles at about 130 to 140 in winter and 160 to 170 in summer. Might creep up to 175/180 at prolonged high speeds (70 to 80 mph) - motor way type driving. Gauge also tested and reads accurately. I sometimes wonder about the pulley ratios I am running and hence fan speed in relation to the engine RPM. I have what I think may be an odd combination and this would affect the pump speed. Is this likely to make a difference? I have the MGB damped crankshaft pulley and a hybrid pump pulley on the MGB pump. I say hybrid, because I had to drill extra holes in the fan hub and put shims in place to get the correct fit and pulley alignment." Lindsay responded: "I wouldn't think it would make a lot of difference Steve. Perhaps if the pump ran way too fast you might get cavitation, but that would cause overheating. I suppose that the fan blowing cool air over the outside of the engine is going to have some effect, but I wouldn't have thought it would stop the engine getting to normal running temperature. If the thermostat is closed, the coolant should circulate within the block and head until the temperature gets to 180F or thereabouts. Steve,this may be of interest.Because of the postings about fan blades breaking and wreaking havoc with anything or anybody that gets in the way, I have recently removed my fan blades and fitted a thermostatically controlled electric fan in front of the rad. This is how my cooling system now behaves. From cold, with the car stationary, temperature rises to about 175F and warm water suddenly starts to be felt in the radiator. Engine temperature then remains at about 190F for several minutes, and then starts to rise to 210F, where I have set the fan to cut in. Over a space of 3-4 minutes, it takes the temperature back down to 190F, when it cuts out, and the cycle begins again. On the road, and thrashed unmercifully, the temperature remains under 190F and the fan doesn't start until the car comes to a halt for a period of time. This, I would say, is pretty normal behavior for a standard 1500, and I would have thought the 1800 would behave similarly in the same chassis, but it could be that the 1800 is a cooler running engine. As I said before, the better type of radiator shouldn't really make any difference until the ambient temperature gets a lot higher than it is now, so it must be for some other reason that your engine is running cooler than what I would think is normal. I am wondering whether my electric fan system is going to keep up with the summer heat when we get it. If not, I will have to refit a mechanical fan. That would be a shame, because the engine is definitely more responsive without it. I will let you know how it performs when we get some heat." |
| Steve Gyles |
| Lindsay Most interesting thoughts. I had always viewed others fitment of a thermo-coupled fan as an additional means of getting the temperature down in hotter climates. But you are correct, such a fan could also assist in getting the temperature up! Could you give me some more details of what fan you used please? Fitment options, where the sensor attaches to the engine etc. I am not the only one to have this low temperature situation. As I mentioned in the previous thread Dominic ran even cooler than me and went as far as fitting a radiator blind. There are 3 common factors with both my engines: The pitch of the radiator slats, the original spec radiator and the fan. I have just gone out and had a look at the car. The shims I fitted were in fact required to push the standard fan about 1/4 inch forward to give clearance with the generator/alternator bolt. I also measured the fan pitch at 27 degrees. Is this more coarse than the standard or about right? If more coarse it could account for more air being drawn through the radiator. Could someone measure theirs please? Steve  |
| Steve Gyles |
| I just carried out an experiment. I blanked off exactly half the radiator (the centre section) and then went for an identical run as yesterday. The temperature steadily rose to 165 F. I then removed the blanking paper and the temperature dropped back to a steady 135 F. The only difference was an ambient temperature about 5 F greater than yesterday. My logic says that the fan and radiator between them are doing a very efficient job. Steve |
| Steve Gyles |
| Steve, a test of the stat would be to take it out, put a blanking piece in and then see what happens. If I remember correctly from the last time this came up there's a small hole that allows some flow past the stat when closed so perhaps this should be included. I cannot believe that the temperature will stay low under these conditions -if it does you've got the first air cooled mga. |
| J H Cole |
| Luckily Steve, you didnt title this thread "Getting it up"! or there would have been little or no response to your thread. Oops! maybe I should have worded that differently! Amongst my winter projects are the fitting of an electric fan and also a harmonic crank balancer pulley. I have been waiting for Lindsays final verdict on his new electric fan before I go out and buy one (and I need to pay Dominic for his pulley) You will recall that my injection moulded fan tends to overcool my engine (runs at 165 degrees) and also creates a lot more fan noise than I would like. I am fairly confident that an electric fan on its own will control my engine temperature ok. I was wondering if your harmonic crank pulley was the reason that you had to space your generator pulley to align with it. I am just trying to prepare the groundwork for my fan conversion and to be ready for the likely snags. I will check fro you tonight to see what angle my old metal fan blades were set at. Cheers Colyn |
| Colyn Firth |
| Colyn Off topic. I think we share a similar sense of humour. Try this one that is doing the rounds: Voted Best Joke in Ireland John O'Reilly hoisted his beer and said, "Here's to spending the rest of me life, between the legs of me wife!" That won him the top prize at the pub for the best toast of the night! He went home and told his wife, Mary, "I won the prize for the Best toast of the night." She said, "Aye, did ye now. And what was your toast?" John said, "Here's to spending the rest of me life, sitting in church beside me wife." "Oh, that is very nice indeed, John!" Mary said. The next day, Mary ran into one of John's drinking buddies on the street corner. The man chuckled leeringly and said, "John won the prize the other night at the pub with a toast about you, Mary." She said, "Aye, he told me, and I was a bit surprised myself. You know, he's only been in there twice in the last four years. Once he fell asleep, and the other time I had to pull him by the ears to make him come." Steve |
| Steve Gyles |
| Steve, I had a reaaly good laugh reading your Irish joke. I think it is hilarious. Ha Ha Ha Ha Ha . Frank |
| F Camilleri |
| Colyn, I have the 1800 5 bearing engine and harmonic balance pulley. I didn't need to add any shims between the fan and pulley but I am still using a dynamo rather than the alternator that Steve uses. ...JB |
| John Bray |
| Colyn, I can't give you a proper verdict on the electric fan until the warm weather comes. Under the present cold conditions it works well, but will it shift enough air through the rad when things get hot.....? Steve, my electric fan is the Revotec kit specially made for the MGA. I got mine from the MGOC. The sensor (which is adjustable) fits in the top hose. Everthing you need is in the kit, including all the wiring. I'm beginning to wonder whether it is a characteristic of the 1800 engine to run cooler. Is the compression ratio lower than the 1500? |
| Lindsay Sampford |
| Steve You say you tried a variety of stats that all worked correctly. I assume this is in a pan on the stove with a thermometer. Surely if you choose say the winter stat that opens at 88degC (190C), that will be closed until the engine reaches that temp. An engine can't possibly run as low as 130degF (54C) with that stat working as it should. Within limits, I don't think fans, engines, or radiators should can cause things to run too cold with a good stat. Pete |
| Pete Tipping |
| Steve, maybe you have a casting defect in the block that creates a T/S bypass? |
| Art Pearse |
| I have the same experiences as Steve. And I have tried various thermostats with absolutely no effect at all. My car runs so cold in cold weather that I can get ice on the carb manifold, directly above the exhaust manifold. It doesn't run above 50C on a cold day. I have checked the gauge against an IR thermometer, and it's working spot on. To address this I have fitted a radiator blind that can be operated from the driver's seat. I also have the rare radiator muffs that I can use when it's really too cold to be in the MGA at all... In summer, even with 35C ambient temperatures, as long as the car is moving, the temp sits at 70C all day long, up mountains along the roads, and a little bit cooler on the long downhills. If sitting in traffic, I may see 80C tops. Once stopped after a hard run, the gauge can climb over boiling point and the cooling system will dump a little coolant out of the overflow if I have topped it up recently. The radiator is an original casing with a standard spec core - no high performance changes here. The oil cooler is fitted with a thermostat. |
| dominic clancy |
| Thanks for that Dominic. It makes me feel better when I see someone else with the same problem. It cannot just be my engineering. There has to be some common MG factor that makes some of the cars act like this. I still want to discount the fan blade pitch angle. I hope a few of you can measure yours and report back. I just have a niggling feeling that there may be a batch of 6-bladers that have a coarser pitch or may have migrated from other MGs. Steve |
| Steve Gyles |
| Dominic, is yours an MGB engine? |
| Lindsay Sampford |
| Hi Lindsey, No, its a 1622 |
| dominic clancy |
| You chaps are probably lucky, it is the opposite here in Oz where many (if not all?) MGA's get pretty hot in summer. I find that rodding out the radiator every four years or so overcomes the problem. It seems that there is some fundamental problem with MGA cooling systems, I thought that it was due to insufficient air flow through the radiator/engine compartment (perhaps grille slats or bulkhead and the oval air vents point to this?) but perhaps not so! As a matter of interest when I took my 1600 roadster to the UK some years ago and entered it in the MG Silverstone Concours, mine was the only car (alongside the UK/European entrants) not fitted with a electric fan! |
| Barry Bahnisch |
| Barry On my car I have had the issue on 2 separate engines and both the original radiator and its replacement that was to original spec that I fitted about 5 years ago. The new radiator was fully flushed 12 months ago. As I said above, the only common items to my running cool have been the original spec type radiator, the fan blades and the angle of the angle of the grill slats. Everything else that could reasonably be associated with cooling system has, at one time or another, been changed to nil effect. It just seems strange to me that blocking off half the radiator got everything reading about right, hence my theory about the strength of the fan. Steve |
| Steve Gyles |
| Scanning the web I have come across numerous references to a BMC 6-bladed (hot climate) fan. Not sure if this indicates that there is also a "temperate climate" 6-bladed fan. My car is an export version, ex-California, so it likely is fitted with the "hot climate" fan. I really need to know some measurements (blade pitch angle) from "British car" owners to establish if there were 2 versions of the 6-bladed fan produced. I do not have my original parts list at hand. Perhaps someone could have a look for clues. Steve |
| Steve Gyles |
| I have just got to jump in here! I am an engineer by trade and for quite some time in my career did power train design for yachts and commercial vessels. This included cooling system design. That being said, I am not a thermodynamic engineer. So I will put this into lay terms, because these are the terms I understand. There are two other places besides the radiator the engine can transfer heat. One is through the heater core and the other through the block and head. In the cold of winter (or in cooler climates) these two are more significant because of the temperature differential between the radiating (high temp item) media as the block and head, and the absorbing media (low temp item) surrounding air. If the thermostat is closed these are the only places that the engine can loose heat. And it will. I once had an Alfa (all aluminum engine) that just could not get hot without blocking off the radiator. Why? The aluminum block was so efficient at heat transfer that the cold air coming into the engine compartment was sufficient to cool the engine below the temp that the thermostat was designed to open. Muffs and radiator blinds were available and common for cars used in cold climates in the fifties and sixties. I also had a Volvo that had a radiator blind and would not get warm in the winter without pulling the blind up. In conclusion, then, Steve and Dominic are not wacked (at least not about their car's cooling) and are indeed experiencing what they tell. My advice to them is to block off the radiator and be happy. I believe that Dominic uses a period blind and Steve like myself back in the sixties uses cardboard. And here are some general comments to statements made above: Original MGA radiators have folded cores and cannot be rodded out. This may be different in OZ, but for Great Britain, Europe, and North America it is true. The only way to clean them is to boil. These cores are very efficient and when cleaned will properly cool any MGA engine even in hot climates as long as the rest of the cooling system is proper. That is to say the block and head are clean, the thermostat is of the proper design, and the water pump internals and impeller are not worn out. Both the pump internal body and the impeller can be corroded and eroded to the point of loosing pump effiency. Dominic's intake gets frosted because he has a supercharger. This is common with long intake runs on supercharger units such as found on Judson and Shorrock types. All this being said, a properly maintained MGA with the stock cooling system should stay cool in the summer months and remain cold in the winter without blocking off the radiator. Barney, are you out there? Jump in on this one. As for funny stories, my fathers favorite was the one about the old guy who's friends decide to buy him a hooker on his 90th birtday. When she arrives at the door, she joyfully anounces "Hi! I am here to offer you Super Sex". The old man thinks for a moment and replies "I'll take the Soup". |
| James Johanski |
| Thanks to Johanski for confirming I am not imagining things! I actually had cool running problems even on the same engine without the Judson. The Judson just accentuated them to the point that the blind was necessary. I also think that a stock system should provide more than ample cooling if it's not full of assorted scale and rust, and provided that the engine is not coated in half an inch of oil encrusted cr*p. I suspect that many overheating issues are a combination of timing that needs retarding a little for unleaded fuel, and a slightly lean mixture. Steve, both the 1600 and 1500 SPLs are online on my site. Both refer to the same fan part number, but the 1600 list shows a change of some sort but doesn't list a replacement part or describe the change. Maybe a later edition of the SPL will shed more light on the subject. |
| dominic clancy |
| I have been summoned? I have been trying to stay out of the "religious wars". This subject has been beaten to death in recent years. I have posted multiple pages on my web site to deal with the logic, but apparently not everyone reads it (or maybe some don't believe in logic). I will condense it now. 1.) I have long been convinced that original cell core radiators with the wide convoluted fluid flow tubes are more efficient than any modern smooth bore vertical tube radiator core (regardless of fin or tube density). Back in the 1960's when I drove MGA cars with all original parts (including the cell core radiator), the cars never ran much over 190dF in hottest summer weather. I don't remember exactly how cold they ran in the dead of winter, but certainly low enough to kill effectiveness of the heater (definitely 160dF or lower). I did block off part of the radiator, sometimes as much as 5/6 of the front surface during 0dF ambient, to bring fluid temperature up to "heating" temperatures (180-190dF). I do not need to do that today. With with a 195dF thermostat it will run at 190dF with ambient air temperature of 0dF (but then runs a little too warm in summer). In retrospect, back in the 60's I don't recall ever checking the temperature rating of the thermostat in any MGA that I was driving. My best guess is that they were likely all 160dF thermostats, which are too low for the heater to work during cold weather driving. 2.) Original cell core radiators are exceedingly rare these days (I wish I had one, and maybe someday I will again). Reports of over cooling with the MGA are likewise exceedingly rare (but real), and seem to be always related to the original cell core radiator. The inference here is, anyone who is genuinely worried about over cooling could change to a modern VT core radiator to banish the problem. Of course you may then get to deal with hot running in warm weather (like the rest of us). On the flip side, I don't believe the cell core radiator is the cause of over cooling. 3.) As a casual observation, it seems like MGA with superchargers may run a little cooler. This may be a side effect of positioning the carburetor in a cooler location farther away from the exhaust manifold. Reason may be because SU carburetors of H or HS type are temperature sensitive and run lean when hot. 4.) If you block off half of the radiator and the running temperature goes up, this indicates that there is indeed warm fluid circulating through the radiator. Assuming that the thermostat is fully closed (as it should be at these abnormally low fluid temperatures), then fluid flow has to be bypassing the thermostat. However, fluid going through the bypass port in the cylinder head goes back to the water pump, not through the radiator. Therefore, if the radiator is the least bit warm there is fluid passing through the thermostat, no argument available, and the thermostat must be defective (not fully closed). 5.) If you don't believe this last line you can install a tin can lid in place of the thermostat to completely block flow, in which case the radiator will run stone cold with no fluid flow, and the engine will most likely over heat. This being the case, then a properly operating thermostat WILL bring coolant temperature up to normal specified operating temperature any time the engine has time to warm up. It is my contention that no MGA can run too cool with zero fluid flow through the radiator, even in sub-freezing ambient temperatures. The iron engine block and head will not air cool enough to do that. As noted above, blocking air flow through the radiator will raise coolant temperature even at 0dF ambient. Even the folks using a radiator blind note that this is true (which is why the radiator blind actually works). 6.) In light of the prior paragraph, it is my opinion the the optional radiator blind may be useful if you drive in cool weather with no thermostat, or if you use a low temperature rated "summer" thermostat all year round, or a faulty thermostat that doesn't close at low temperature. In other words, use of the radiator blind can relieve you of the twice annual chore of swapping out the thermostat. Or the racer types can run with no thermostat by using the blind to manually control coolant temperature. I suppose the "over cooling" bunch actually prefer operating in this mode, and/or have not tried the tin can lid to prove that their thermostat is faulty. Bottom line is, I refuse to believe that any MGA can be over cooled when running a properly functioning thermostat with high enough opening temperature rating. Now go ahead and take your best shot, as I am Teflon coated with a bullet proof vest. |
| Barney Gaylord |
| I have been summoned? I have been trying to stay out of the "religious wars". This subject has been beaten to death in recent years. I have posted multiple pages on my web site to deal with the logic, but apparently not everyone reads it (or maybe some don't believe in logic). I will condense it now. 1.) I have long been convinced that original cell core radiators with the wide convoluted fluid flow tubes are more efficient than any modern smooth bore vertical tube radiator core (regardless of fin or tube density). Back in the 1960's when I drove MGA cars with all original parts (including the cell core radiator), the cars never ran much over 190dF in hottest summer weather. I don't remember exactly how cold they ran in the dead of winter, but certainly low enough to kill effectiveness of the heater (definitely 160dF or lower). I did block off part of the radiator, sometimes as much as 5/6 of the front surface during 0dF ambient, to bring fluid temperature up to "heating" temperatures (180-190dF). I do not need to do that today. With with a 195dF thermostat it will run at 190dF with ambient air temperature of 0dF (but then runs a little too warm in summer). In retrospect, back in the 60's I don't recall ever checking the temperature rating of the thermostat in any MGA that I was driving. My best guess is that they were likely all 160dF thermostats, which are too low for the heater to work during cold weather driving. 2.) Original cell core radiators are exceedingly rare these days (I wish I had one, and maybe someday I will again). Reports of over cooling with the MGA are likewise exceedingly rare (but real), and seem to be always related to the original cell core radiator. The inference here is, anyone who is genuinely worried about over cooling could change to a modern VT core radiator to banish the problem. Of course you may then get to deal with hot running in warm weather (like the rest of us). On the flip side, I don't believe the cell core radiator is the cause of over cooling. 3.) As a casual observation, it seems like MGA with superchargers may run a little cooler. This may be a side effect of positioning the carburetor in a cooler location farther away from the exhaust manifold. Reason may be because SU carburetors of H or HS type are temperature sensitive and run lean when hot. 4.) If you block off half of the radiator and the running temperature goes up, this indicates that there is indeed warm fluid circulating through the radiator. Assuming that the thermostat is fully closed (as it should be at these abnormally low fluid temperatures), then fluid flow has to be bypassing the thermostat. However, fluid going through the bypass port in the cylinder head goes back to the water pump, not through the radiator. Therefore, if the radiator is the least bit warm there is fluid passing through the thermostat, no argument available, and the thermostat must be defective (not fully closed). 5.) If you don't believe this last line you can install a tin can lid in place of the thermostat to completely block flow, in which case the radiator will run stone cold with no fluid flow, and the engine will most likely over heat. This being the case, then a properly operating thermostat WILL bring coolant temperature up to normal specified operating temperature any time the engine has time to warm up. It is my contention that no MGA can run too cool with zero fluid flow through the radiator, even in sub-freezing ambient temperatures. The iron engine block and head will not air cool enough to do that. As noted above, blocking air flow through the radiator will raise coolant temperature even at 0dF ambient. Even the folks using a radiator blind note that this is true (which is why the radiator blind actually works). 6.) In light of the prior paragraph, it is my opinion the the optional radiator blind may be useful if you drive in cool weather with no thermostat, or if you use a low temperature rated "summer" thermostat all year round, or a faulty thermostat that doesn't close at low temperature. In other words, use of the radiator blind can relieve you of the twice annual chore of swapping out the thermostat. Or the racer types can run with no thermostat by using the blind to manually control coolant temperature. I suppose the "over cooling" bunch actually prefer operating in this mode, and/or have not tried the tin can lid to prove that their thermostat is faulty. Bottom line is, I refuse to believe that any MGA can be over cooled when running a properly functioning thermostat with high enough opening temperature rating. No go ahead and take your best shot, as I am Teflon coated with a bullet proof vest. |
| Barney Gaylord |
| Dang. I swear I don't know how the double posting happened, but too late to delete it now. |
| Barney Gaylord |
| It was worth reading twice Barney! |
| Lindsay Sampford |
| Well Barney, that told us! Twice!! I have to hold my hand up and admit that I havent read through your MGA Guru section on this subject, but I will now. Thanks again Barney. Im lucky in that (so far ) my MGA runs fairly cool (usually 165 degrees F) and Im fairly sure it has a modern radiator core fitted. I do have an original radiator on the shelf in my garage and it would be interesting to fit it to see what happens. I will let you all know if the running temperature drops below freezing! Colyn |
| Colyn Firth |
| Has anybody out there run an MGA with just an electric fan, and no pump-mounted fan? |
| Lindsay Sampford |
| Barney I totally agree with your comments about the original spec radiators. I have frequently advocated their benefit on this forum. I have personally witnessed a colleague's car transformed from an over-heater to standard operating temperatures with an original spec radiator. Mine is as close to original as it is possible to get in the UK, so I am advised by Bob West. He has a specialist rebuilder doing all his radiators. I still have my summer stat fitted only because all my spares are currently in storage. I can nevertheless confirm that my stat is working ok and the radiator got fully hot the other day (the gaffer tape holding the paper shield in place had virtually melted its stickiness on the radiator header tank and parted company). I might try to source a winter stat tomorrow, although it made little if any difference last winter. I guess that was why I had not yet got round to it this year. I am still intrigued by the fan. I can only assume that the early 4-blade fans did their job adequately in the UK, but the USA market required the additional cooling, hence the 6-blader. Have you any knowledge of different versions of the 6-blader or were they all the same? Steve |
| Steve Gyles |
| Another couple of (boring) comments! Many years ago an Australian core manufacturer recalled all finned tube replacements and had cellular (the original design) cores fitted free of charge. Apparently this was due to the large number of complaints about overheating. I was one of the owners but can say that it made no discernable difference (and my two 1600's have the different cores to this day, and both get hot!). My other comment is that Mk 2's had vertical grille slats (as did MGB's), I am inclined to think that there was insufficient air flow through the radiator in earlier MGA's. |
| Barry Bahnisch |
| Short summary on fans, belts and pulleys (details below): For 1500/1600 engines the cooling fan never changed. Dynamo pulley and V-belt changed once in early 1500 production, then changed only briefly (124 cars) in early 1600 production, then returned to prior number. Note that (e)16GA/H31660 is end of 1600 production. I have no record of any change of these part numbers due to 1622cc engines. ------------------------ 1500 fan = AEG129 1600 fan = AEG129 Fin. (e) 16GA/H31660 1500 belt = 16G2716 = 1H1001 com. (e)15GB17061 1600 belt = 1H1001 = 1G2716 com. (e)16GA/H6272 (not available use 13H923) = 1H1001 com. (e)16GA/H6396 fin. (e)16GA/H31660 or 13H923 com. (e)16GA/H6396 fin. (e)16GA/H31660 1500 Dynamo pulley = 2A412 = 1H998 com. (e)GB17061 1600 Dynamo pulley = 1H998 = 12H71 com. (e)16GA/H6396 fin. (e)16GA/H31660 1500 Fan pulley = 11G200 1600 Fan pulley = 11G200 (11G200 not available use 8G742) = 8G742 fin. (e)16GA/H31660 |
| Barney Gaylord |
| Barney, Thanks for jumping in! You are teflon!! You did not answer my statements on heat loss through the engine block and heater. Heat loss through the block can be as much as 1/3 of the total heat produced by the engine and this is more noticeable in cold weather coupled engine spaces that have plenty of air circulation. Blocking off the radiator (or grill) reduces this cooling effect considerably. Again the reason for radiator blinds and grill muffs. I think mostly that we are in agreement and the cold temps that Dominic and Steve experience are a product of cold ambient temperatures. I agree that if you block off the themostat orifice with a tin plate the engine will over heat, but in cold weather with the heater on this will be delayed. The colder the weather the longer the delay. If one has a 160 degree thermostat mounted, the engine will indeed feel cold in the winter and this combination in the summer will yield engine temps in the 180-200 range. All of this of course assumes use with a folded core radiator. In summation I agree with you on 1, 2, 5, 6. On item 3 the manifold frosting observed on long run intakes is cause by fuel cooling--same thing happens on the suction side of a fuel line. On item 4, you did no comment on the effect of blocking the radiator has on air flow in the engine compartment. To my point I offer this side bar that on tightly enclosed marine engine spaces with no air flow, there is almost always overheating of the engine because of the lack of cooling available through the block surface. Same for a car. If you would like a folded core radiators, give me pm off line--I can build one for you. |
| James Johanski |
| James, -- I think I did answer the bit about heat loss through the engine block and head (paragraph 5a). I recon even at 0dF (-18dC) ambient with the radiator air flow completely open and coolant flow completely blocked from the radiator, the engine cannot air cool enough to prevent overheating when running continuously. If you stop the coolant flow through radiator completely, then this has nothing to do with type of radiator core. Been there, done that. When I was driving regularly in sub-0dF in the late 60's (daily for a few weeks on end), I always had to keep a small part of the radiator (about 1/6) open to maintain correct operating temperature without overheating (pegging the temperature gauge). From the other point of view, I have never tried the tin can lid in place of thermostat to stop fluid flow through the radiator. However, if you contend that free air flow only with no fluid flow in the radiator would air cool the engine enough to retain low operating temperature (135dF for instance), then a properly operating thermostat would never open, which would be exactly the same as a tin can lid. In my case (in the late 60's), even after overnight sit in -10d ambient, the engine (with unrestricted air flow would eventually warm up above 150dF, and some fluid would pass through the radiator, as verified by a warm radiator core. That means the thermostat was no longer fully closed (low temperature stat). In more recent years I have also driven my current MGA in -10dF weather with similar results. With unrestricted air flow It always warms up enough to get some noticeable heat from the heater. With high temperature thermostat (180-195dF ratings) it will always get good heat from the heater (185dF coolant temperature) after some running time. There is no way this thing would stabilize below 150dF running temperature with the thermostat closed. If y'all are interested, I intend to drive it 25 miles each way to a club natter 'n' noggin this coming Tuesday night, 6:30p departure, 11:00 pm return. Forecast temperature for Tuesday here is 0dF night before, 11dF day time high, and 4dF night time low. Is that cool enough for a good test? If encouraged, I could park it outside for 24 hours the night and day before this run. |
| Barney Gaylord |
| Barney, Apologies to you if I am not understanding what you say. I understand that the entire engine cooling cannot be accomplished through the block. But this cooling is significant and amplified in cold weather. I think you agree with that--Yes? Stay warm. |
| James Johanski |
| "Bottom line is, I refuse to believe that any MGA can be over cooled when running a properly functioning thermostat with high enough opening temperature rating. " Barney, I (like Steve) have tried various thermostats (currently I have a 80C one installed) which have made not a single degree difference in operating temperature. I have tested them in my kitchen, and they open as expected at the correct temperature. I also tried a blanking sleeve - which also made no difference. The temperature only rises when I close the radiator blind, even on a cool summer day. Once it is up to operating temp I can open the blind partially and the temp will drop immediately till I have found the correct setting to keep the temp stable So while your theory may be 100% bulletproof in your mind, the reality is unfortunately not as the theory predicts. Otherwise the implication would be that the IR thermometer, temp gauge, thermostat are all faulty on my car, and that water boils at a signficantly different temperature in Zurich (at 550 Metres) than it does in Michigan. |
| dominic clancy |
| Scientific type of question: Does the ratio of antifreeze to water have any effect on the rate at which the mix can be cooled down in the radiator? Steve |
| Steve Gyles |
| Steve, water has a higher thermal conductivity than glycol (or organics in general) so no A/F helps, but only a small effect b/c the greatest resistance to heat flow is on the air side. |
| Art Pearse |
| Steve/Dominic - this really puzzles me - how an engine can run so cool with a working thermostat. When I first run mine, the temperature rises steadily to 190 in the first mile or so and then suddenly drops backs to about 130 as the thermostat opens. It then climbs back up to 190 and then drops back to around 150 and then to 190 again, where it stays unless I get in standing traffic for more than about 10 minutes (original radiator). Barney's theory sounds Ok - I would love to know why/how your 2 cars break the theory - will have a look at my fan blade angle this week. |
| Cam Cunningham |
| Cam Went for a drive down to our local Halfords to get an MGB winter thermostat. I kept my beady eyes on the temperature gauge all the way. OAT was about +3C. For starters, I was able to put the choke pull fully in within about 1/2 mile. During the same distance, the temperature gauge came off the stops. It then increased slowly during the next mile to 120F. After my purchase (yes, held in stock by a normal high street motor factor) the gauge edged up to 135F in town traffic and then settled down at 130F in the clear run home. Switched off and the gauge rose steadily to 160F. That's the sum total of it. The highest the gauge showed today. It was almost as if the gauge was damped. No swinging around between maximum and minimum. Just a gentle stroll up the gauge. The sort of thing I see on my modern day Merc from cold. In fact identical. Too cold to fit the stat. Watched a war film on TV instead! Steve |
| Steve Gyles |
| Cam Went for a drive down to our local Halfords to get an MGB winter thermostat. I kept my beady eyes on the temperature gauge all the way. OAT was about +3C. For starters, I was able to put the choke pull fully in within about 1/2 mile. During the same distance, the temperature gauge came off the stops. It then increased slowly during the next mile to 120F. After my purchase (yes, held in stock by a normal high street motor factor) the gauge edged up to 135F in town traffic and then settled down at 130F in the clear run home. Switched off and the gauge rose steadily to 160F. That's the sum total of it. The highest the gauge showed today. It was almost as if the gauged was damped. No swinging around between maximum and minimum. Just a gentle stroll up the gauge. The sort of thing I see on my modern day Merc from cold. In fact identical. Too cold to fit the stat. Watched a war film on TV instead! Steve |
| Steve Gyles |
| After my last post I got thinking about the temperature gauge transmitter pipe. The correct routing for it from the sensor is along the length of the block, then into a few vibration compensating coils before going entering the bulkhead. When I rebuilt my MGA in 1997 I was not aware of the likes of Clausager and routed the pipe across the compartment to the inner fender. About the first foot of the tubing is therefore broadside on to the fan blast. Could it possibly be that I am 'super cooling' the fluid/vapour in the pipe as it transmits from the sensor? Looking for answers to this strange situation, so this is just perhaps a wacky thought...... Steve  |
| Steve Gyles |
| Steve - I'm going blue here holding my breath waiting to see what happens with that nice new stat. One wonders; can a stat remain open, if it fails somehow or perhaps if the coolant freezes..? We're waiting Steve... Pete |
| Pete Tipping |
| Hi Steve You may see a small effect by cooling the pipe more than the standard routing but the bulb in the block has a large volume compared to the pipe I expect (if it was designed properly!) and the guage reading will depend on the relative volumes of fluid in the pipe and bulb at the different temperatures. If you knew the volumes and temperatures you could calculate the variation for the sections of the pipe and bulb. That would be an interesting little spreadsheet exercise. I am curious about James' point. If the cooling from the block and heater core alone is high enough then the thermostat won't open. Blanking the radiator will reduce the block cooling as well when moving. However, I doubt whether there would be enough cooling just from the block especially when staionary. For Steve and Dominic are you sure the radiator/top hose doesn't get warm at all. That's probably the sure indication that the thermostat is shut completely or no flow is going through the radiator. Also does turning the heater off make any difference to the temperature guage. Steve you could put a rubber bung in the top hose and see what happens! I have another question on all this. I was wondering what is the most efficent temperature for the engine to run at or temperature which gives most power. I found this article on the A series engine which suggests that 70 to 75 deg C is optimum power but useless for the heater. http://www.minispares.com/Articles.aspx?ty=ad&aid=267 |
| John Francis |
| Steve I should have said put a bung in the thermosat housing not top hose (when the car is stationary). I'm assuming the pump flow is from thermosat out to the radiator rather than the other way. The Mini article had some interesting comments about fan blades and electric fans effectiveness at different vehicle speeds. |
| John Francis |
| Having just updated PDF files on my web site for the 1600 and 1600-MK-II SPL, I can follow up on parts used in the cooling fan drive system. The 1600-MK-II with 1622 engine used all the same parts here as the 1600 engine, except there is one new part number for the dynamo pulley. Dynamo pulley original part number = 12H71 com. (e)16GA/H6396 New part number = 12H1178. 12H71 not available, use 12H1178. No change of any other parts in the belt drive system, so it appears the new part is essentially same as the old part. Guessing it may have a steel hub in place of cast alloy, or maybe something simple like different rivets. Otherwise it has to be physically interchangeable. Bottom line is, same cooling fan was used throughout all MGA production. |
| Barney Gaylord |
| James, -- Yes I said that the entire engine cooling cannot be accomplished through the block via external air cooling. I also agree that block air cooling is significant and amplified in cold weather. But the point still stands that the engine would overheat if there is zero coolant circulation in the radiator, even in very cold weather. One follow up question for Dominic for clarification. On 10 December you wrote, "It doesn't run above 50C on a cold day". That would be 122dF, which is far below opening rating of any factory specified thermostat. So the specific question is, when it runs around 50dC on a cold day (presumably stabilized after engine warn up), is the radiator a little warm or very cold? Reason for the question is, if there is any warmth in the radiator at all, this indicates some fluid circulation, which means the thermostat is not closed as it should be. |
| Barney Gaylord |
| Some very strange phenomina reported here. I have to say if my engine block coolant was running at 50deg C I would be laying an egg ( an ostrich sized one!) It sounds thermally inefficient and possibly damaging DeltaT stress wise for the the block... It is an academic problem here in Oz luckily however but intriguing. My expereince and reading always led me to believe that you should run up to close to boiling but leave enough margin so that a sudden extra and continuous demand on a hot day did not take it over the top. This is good thermodynamically ,block stress wise ..and oil should be chosen to match. The above leads me to use a thermostat setting of about 185deg F and I use twin pusher electric fans ( no pulley driven fan ) and set them to cut in about 195 and out at 185. The water stays within a very narrow band and even hard driving up a sustained steep incline over the Great Dividing Range near my house does not drive it above 205Deg f. I read the article ref by John Francis above and they actually recommend 185 to 190degF so that is consistent. Any way back to low temps.... I believe you two guys must have coolant bypassing your thermostats or have another pathway ( difficult to envisage )..and the wee sweaty hand ( in fingerless gloves in the UK right now) on top of the radiator should verify this. Recommend you all get electric fans and stop unnecessary and harmful cooling by the pulley driven fan at low ambient temps and reliance on poor quality thermostats fitting on corroded /eroded seats. ..Great jokes, Steve and Johanski..my family and friends loved them. Lets forget about MGAs and just exchange patter. |
| Neil Ferguson |
| Steve, I agree with Neil in that there must be some fluid "leaking" when the thermostat is closed. The exposed capillary will not make any difference. Incidentally, the 1500 routing was also across there to the inner wing. One question though; did you check the calibration of temperature gauge? If it is a reconditioned gauge it could quite easily be reading low (depending on who reconditioned it!!) I have a feeling you may have already said you checked it, but it's easy enough to do and it would be good to rule it out of the equation. |
| Neil McGurk |
| Neil and others I will be going out into the garage in a few moments to change the thermostat to an MGB winter version. 82C (180F). It made absolutely no difference last year, but let us see what happens. One thing at a time - yet again. I have never yet found anything wrong with any of the bits I have checked or replaced. I had the engine out a year ago for an inspection/light overhaul and repaint. All looked like it should do. No mysterious bypass channels etc! Also please bear in mind what I said earlier that this also happened with my previous (1500) engine, so a completely different thermostat, housing, block, head and pump etc. I think the radiator accounts for a lot, as discussed with Barney. I will do a run out in the car first and do a 'hands on' check of radiator, pipes, block etc. Might take a few photos so you can see what is happening. Steve |
| Steve Gyles |
| Neil, you may have partly answered my question "Has anybody out there run an MGA with just an electric fan, and no pump-mounted fan?" posted above. I say partly, because you have two electric fans, and I have just the one. I have dispensed with my pump mounted fan and fitted an electric, thermostatically controlled fan for two reasons. 1). For safety. A fan blade breaking off could be catastrophic or even fatal if someone were hanging their head over the radiator with the engine running when it happened. And 2). For performance and economy. The pump mounted fan runs all the time, whether is is needed or not, soaking up energy and, dare I say it, cooling the radiator and engine when it is not required. My only concern is whether or not the electric fan will be able to dissipate enough heat in the summer months when the car is stationary in traffic.If Neil's two fans can do the job in Australian heat, I hope my single one will be enough for the UK summer. Anyone else had experience with an electric fan only on an MGA? P.S. Neil, I have set mine to cut-in at 210F so that it cuts out at 190F. If I were to set the cut-in any lower, the fan would probably not cut-out, as my normal running temperature on the road is around the 190F mark. |
| Lindsay Sampford |
| Steve, we are working back towards that beastly temp gauge! (Incidentally, my sensor pipe is routed the same way as yours, and I get nice high readings.). Perhaps everything is right with yours and Dominic's engines, but the gauge is telling you something else! |
| Lindsay Sampford |
| Just done a 10 mile run. The picture shows the maximum temperature reached by the end. When I stopped I was just able to put my hand on and leave it on the radiator header tank, top hose, engine block, cylinder head etc. I agree that indications would suggest thermostat stuck open, but we shall see. I have been down this route before and found nothing wrong. Just warming up before I dismantle. I hope I am wrong this time and find something untoward. Steve  |
| Steve Gyles |
| Steve, that's where my temp gauge is after 3 or 4 minutes at 1,000-1,500 rpm from cold! Does your heater work at all? |
| Lindsay Sampford |
| Steve, I know its a pain but I agree with Barney's suggestion that the definitive test is to take the thermostat out and put a blanking piece in. You don't even have to drive the car just keep the revs up for a while. In my opinion its just not possible to dissipate the heat quickly enough to stop the engine boiling. |
| J H Cole |
| On the temp gauge subject, when I first got my car the needle never went above 100 degrees F even though the engine was fully warmed up. On investigation it turned out to be the gauge glass had slipped a little preventing the needle from reaching its correct position on the dial. (Then the normal temp showed 175 degrees but more recently, since fitting the larger and more efficient injection moulded fan, it now runs at 165) Probably isnt the reason for your lower reading Steve but worth a look. Colyn PS Like Lindsay, I am really interested to hear if anyone in the UK has totally replaced the standard fan with an electric one. |
| Colyn Firth |
| Well, some success. I took the old thermostat out, it was fully closed. It was in fact an 82C stat. As the new one is also an 82C I put them both in water and heated them up. The old one started opening about 10F before the new one, certainly no more as it was only about 10 to 20 seconds apart on the stove. Unfortunately the thermometer is also in store so I cannot be exact. They both then closed off fully. The test run got the temperature up to 170F but would not go any higher. That is as it happens the highest normal running temperature I get even in mid summer except when in heavy town traffic. The new stat was the 4th I have bought in the last 15 months. The one I have just taken out was put in new this time last year. So, there we are. Still looks a bit low but I guess I can live with that for a while. In slower time I will have another look at the accuracy of the sensor. However, it was spot on when I last checked it and the reading I am now getting is the same as a year plus ago. Steve  |
| Steve Gyles |
| That looks like an improvement Steve. I'm sure your engine will be happier and your feet a little warmer! I just ran mine up from cold without driving it. Radiator started to feel warm as the gauge hit 170 and 190 was achieved after 7 minutes. Ambient temperature here is 0 degrees C and I have no pump-mounted fan. My thermostat is the original sleeve type (museum piece!) marked 75C. |
| Lindsay Sampford |
| Lindsay Yes, basically back to where I started late summer. It's still looking low. My fuel consumption figure since March 2006 is 24.28 mpg, so I do not think the low block temperature has helped in that score. I am going to think about going down your route. I guess removing the metal fan would additionally help improve fuel consumption a tadge. With pump prices now up to about £1.23 (US$1.90) a litre 'every little helps'. Steve |
| Steve Gyles |
| Steve, the only thing that concerns me, let alone surprises me, is that I have yet to see an MGA fitted with an electric fan and NO pump mounted fan as well. I can see no point in having both. |
| Lindsay Sampford |
| Looks like you are doing the trial Lindsay! Are you monitoring fuel consumption before/after? If I follow you I will be able to provide very accurate sets of data on that score. For instance, my figures showed a 6mpg increase when I sorted out my master cylinder with slow releasing brake pressure. Steve |
| Steve Gyles |
| Steve, It seems to me that you have two possible areas that could cause low temperature readings. One is that for some reason your gage is not giving you the correct reading. The other is that somehow coolant is getting past/through your thermostat. Is is possable that your thermostat is not sealing around the base where it fits in the block and allowing coolant to flow around the thermostat? I find it hard to accept that you could have that low of engine temperature without some flow to the radiator. It's too bad we can't see down into the top tank of the radiator to see if there is any coolant movement before the engine reaches operating temperature. |
| Ed Bell |
| Ed Thanks for your observations. I can confirm that the new thermostat that I fitted today is a very snug fit. As with the previous thermostat it is bedded down with sealant on both sides of the gasket and it is totally sealed into the recessed housing. No way water can leak round the edges. I am looking at purchasing one of those digital IR temperature sensors that you point at any part of the engine assembly. Hopefully it will reveal some useful data. Steve |
| Steve Gyles |
| Steve Sounds like good news to me and your 170deg reading is not far from the standard 82degC stat you are using. A good all round average for us here. I wonder now why you didn't obtain the 88degC winter stat, I mentioned above, which is around the 190dC you are looking for... I use the 74dC summer stat all year and run at around 160-170 this time of year and gives more of a buffer for the hot moments in the summer when it will run at 180-190 on the move. Sitting stationary mine's away and the electric fan (+ mechanical) will hold it below 200. After switching off, the needle can hit 100psi on the oil scale ! Ticking over from cold, with my hand on the top hose, as the stat opens, its almost like a switch turning on as the pipe heats up pretty quickly from stone cold. Did you ever try that with your old stat Steve? Pete |
| Pete Tipping |
| Ever tried it without the mechanical fan Pete? Steve, I haven't done any fuel consumption figures lately, but when I did it a while ago it was pretty well the same as yours. I never managed to break the 30mpg barrier, but I have never driven the MGA with a view to economy. I stopped recording the fuel consumption, as it got too scary! The engine does seem to be snappier without the fan, I'm sure it's not my imagination. In theory, the lack of a permanently running fan should make no difference at normal road speeds, so whether I refit the pump fan or not, should depend on how the electric fan does when I'm not moving. I will keep you all posted as the weather warms up, so you can put your electric fans on hold if you like. I definitely did not fit the electric fan to augment the pump fan. The pump fan was perfectly adequate, but then, I don't worry as long as the engine runs nicely and the needle stays somewhere on the temperature gauge scale, that is, somewhere south of the 230 mark! I think half the trouble is that our temperature gauges are too detailed. If they just said C-N-H, no one would worry until the needle sat on H, and that would probably be, as Pete said, on the 100psi mark on the oil pressure scale! |
| Lindsay Sampford |
| Lindsay No I haven't or I would have rsponded to that query sooner. I wouldn't have any hestitation at trying it without the original fan though. You would soon get a feel for what is happening and then see how it goes as summer arrives. It's not exactly rocket science to whip out the rad and pop the fan back on! Mind you I don't bother with the untidy fan thermostat which makes things easier. Mine overheats on the engine fan alone so I'm staying with both... Pete |
| Pete Tipping |
| Steve, Have you checked the calibration of the gauge? Stick the bulb in boiling water to check. |
| Neil McGurk |
| Peter, I managed to remove my fan without taking out the rad. A bit of a fiddle, as you can only turn the bolts a fraction of a turn at a time, but do-able. Saves draining and re-filling the cooling system. It might be harder getting the fan back on! |
| Lindsay Sampford |
| You did well to get the fan off like that Lindsay, I tried to remove my fan that way and after skinning just about every knuckle on my right hand just trying to get the ring spanner onto the first bolt head, I gave in and took the rad off. My hands are similar in size to a bunch of bananas though, which doesnt help. Colyn |
| Colyn Firth |
| Colyn, isn't yours an 1800? If it is, maybe the clearance between fan and rad is less, but it was quite tight on mine. Pete, just noticed your mention of overheating with just the standard fan. Was that when stationary or moving, and what do you call overheating? With the standard fan, mine could tickover all day at the standstill and not go above 190F. Labouring up a long hill would get it over 212F, and really pushing on a long fast road would get a similar result, but the temperature would soon drop once I lifted off. In the heat of summer, after a good run, the temperature would sometimes rise to 230F after switch-off. I would call this normal as far as my car is concerned, and I have no trouble with coolant loss, as I have a recovery system fitted. Before fitting the coolant recovery, I was forever having to keep an eye on the water level, as it would always manage to kick some out whenever it got a bit hot and bothered. The only time I have really had overheating was when a faulty distributor seriously retarded the ignition and I did about 30 miles with the gauge on 230F. It got me home without missing a beat, but it was a struggle to do 50 MPH. So all in all, I think they will put up with quite a lot of heat in there. The only time I have trouble with under-bonnet heat is when I re-start the car when it is still very hot. It will stumble for about a minute and then sort itself out, due, I think, to fuel vapour lock. |
| Lindsay Sampford |
| Lindsay. I guess with the 1800 it depends whether you have the short or long nose pump? I have just looked at mine. I can access the bolts, but it would be a bit fiddly as you describe. The fan hub front face is 4.5cm from the radiator and the front edges of the fan blades are 3cm away. Not much room for an electric fan in there or is yours on the radiator front face? Neil. Bit of a game to check the accuracy of my thermostat sensor at the moment without a thermometer. I have no power in my temporary garage at my flat, other than a lighting circuit, so I would need to transport a pan of boiling water through the flat, down one storey, and then across 40m of driveway to the garage. If the the gauge then reads less than 212F is that an inaccuracy or heat loss en-route?! I will probably go and buy a cheap thermometer in the kitchen shop today. I guess a couple of quid makes sense instead of a £50+ IR digital thermometer that will only get used rarely. Steve |
| Steve Gyles |
| Steve, mine is a 'pusher' fan, so it is mounted in front of the rad, but there appears to be enough room to fit it on the 'inboard' side of the rad. Although I haven't taken any measurements, it did look possible to fit the fan that way. I considered it, but it would have meant reversing the wiring to the fan and making changes to the fitment that would have invalidated the guarantee. |
| Lindsay Sampford |
| Skinny Knuckles Sampford I reckon you are describing my car there, however mine has the standard radiator recovery system - the road! I just don't like cooking things up as you describe, I tend to back off to that idyllic top down speed of 40-45mph on hot days and find that gives the coolest running. Any faster or slower, on the level, the temperature rises. This is just those extraordinarily hot days, the rest on the year the car is just magic to me. I had a 1600 when it was two years old and there was none of these issues at all - drove it like I'd stole it, often getting to an indicated 110mph; checked things once in a blue moon... Its got to be down to this funny petrol with less of them octanes and no lead! Pete |
| Pete Tipping |
| Pete, fit a coolant recovery system, I copied Steve's one that appears on his web site. Once you have a car that cannot lose most of its coolant, you can stop worrying. Barney doesn't worry about high coolant temperature! see here http://mgaguru.com/pic89/trmont.htm |
| Lindsay Sampford |
| Hi Lindsay - Its me mate, I've read Barney's brilliant website info and agree totally with every word he writes, but I just like to try and keep it like those guys designed it. Being a design engineer all my working life its a kind of respect for the way things were done and if we change things we are not getting the full experience of how it was. I absolutely hated fitting that electric fan, it was a last resort and much needed for a 24 hour Le Mans trip (being in the Parade des Pilotes was the best thing ever) - now if I had one of Bob West's rads... Pete |
| Pete Tipping |
| Pete, maybe you're right about the petrol we burn now. It seems strange that MGAs all over the world should be running hotter than people like yourself remember them running when they were new. My ZA Magnette, with its original radiator and clean cooling system also ran much closer to the 'H' than the 'N', and that was running a lower compression ratio than the MGA and I would imagine the cam was a bit softer. Whilst on my way down to Devon in September, I had a fanbelt break and, despite the coolant recovery system, lost at least half my coolant before I could come to rest (incidentally, the very overheated engine was still running sweetly as I parked in the "Little Chef" car park!). It just boiled straight through the catch tank and out the overflow. Anyway, my coolant had been 50% OAT antifreeze. After topping up the system again with ordinary Wiltshire tap water, the car ran a lot cooler, so it just goes to show how antifreeze reduces the efficiency of water as a coolant. I have since reduced the antifreeze to 30% of the coolant. |
| Lindsay Sampford |
| We've digressed from Steve's coldness with all this hotness..! A last go. Since my engine was 'hot tanked' and the rad replaced I've only used distilled water with 25% Halfords blue stuff to keep the water percentage up which is fine for our winters + some water wetter. So I know my system is as clean as possible. The coolant is changed every two years and it comes out a blue as it went in. The other thing about letting the engine get very hot is the onset of vapour lock as soon as you hit traffic - that could prove dangerous one day. Roll on spring... Pete |
| Pete Tipping |
| I have just been testing my 1 year old 82C (180F) stat with my new jam, marmalade and confectionery thermometer! The stat was breaking its seal at 130F (warmed my lips testing!) although the movement was indiscernible to my eye. This would tally with my gauge reading settling at 130F. It was visibly open by about 1/8" at 68C (154F). So much for being an 82C stat. I am now a bit concerned about the new one I have just fitted. It started opening only shortly after this one in yesterday's comparison check. It is an identical item. I also need to do a calibration check on my old 1930s thermometer I have in store. It never raised any suspicion with me when I checked other stats and the gauge sensor a year or so ago. May be I did not watch closely enough. It was only marked in 5 degree increments and was only a very small instrument. Seems there is a lesson here to test new stats before installation. Could this be a case of poor quality control again by the manufacturer? Steve |
| Steve Gyles |
| Steve, I would say that your new thermostat is doing its job properly. 170F has got to be a significant improvement over 135F, and almost ties in with the 82C stamped on the stat. The few degrees lower that your gauge is reading could even be an inaccuracy with the gauge itself. You might not be as 'cool' as we thought you were! |
| Lindsay Sampford |
| There you are Steve - sorted. Forget all those fan and pulley ratio worries - have a Happy Christmas... Pete |
| Pete Tipping |
| Pete Optimist! Not happy yet. Why is an 82C stat giving 170 max in a benign environment? Gunned the car today; idled it; and crawled it. Would not budge above 170F. I agree I have yet to calibrate the sensor against my marmalade thermometer but I have every reason to believe it is not reading high. I held the thermometer against the block; against the top hose and against the header tank but could not get a reading above 120F while the gauge was reading 190 (temp after shutdown). No doubt there is a good reason for this and I will swallow my words when I get round to doing a proper test later this week! Steve |
| Steve Gyles |
| Be happy Steve, your thermostat is working, your gauge is reading 5 degrees low, and everyone knows that marmalade degrees are bigger than water ones! |
| Lindsay Sampford |
| More success, but with it comes more problems. My gauge would have been no use for boiling marmalade. It is reading 8F low. My first action when I get my tools out of store is to bin the old 1930s thermometer! I guess it's the same with so many tools, torque wrenches and the like in particular - they need periodic calibration. Lesson for us all there. I have found the pearls of wisdom from you all on this thread most useful and I hope others have picked up some good information as well. I have just looked on Barney's site for fixing the gauge. It seems to be a basic agricultural fix, pull of the needle and put back on in correct position. Thereby lies my problem. How do you get the chrome bezel off? It may be that my hands are just too cold out in the garage but I cannot get it to twist or budge in any way. Before I do any damage can some advise me please. Cheers Steve PS. Tested the thermometer on my bedtime drink last night. Semi skinned milk boils at same temp as water, so in an emergency you could always milk a cow in a field and top up your radiator! |
| Steve Gyles |
| I'm now waiting for your posting that says "How can I get my MGA to run cooler"! You know the answer already, move the needle on your temperature gauge, it works brilliantly! |
| Lindsay Sampford |
| Sorted. Panic over. Finally got bezel to twist. Needle pulls off easily. Now to calibrate. Steve |
| Steve Gyles |
For follow up on my note from 12 December, I did do the 24 hour cold start and warm up test last night. Unfortunately "cold" was only down to 15dF (-10c), so I felt a little short changed, but the test came off well anyway. I will now try to upload the graph I made from the test data. If it doesn't work, or if you would like to see a 2-page article about what it means, see here: http://mgaguru.com/mgtech/cooling/cool_130.htm
 |
| Barney Gaylord |
| Good figures Barney. You certainly have it cold over there. Your area was on our national news the other day with large snow falls. My gauge is now spot on. I don't think my warm-up was a million miles different to yours except it stabilised at 176-178F with my 82 stat. All good fun. It has been an interesting task getting it all sorted. Originally (on the salt on the UK roads thread) I did not post my 130F temp as a problem just an observation. You have to be careful what you say on this forum! Total cost: £5.99 for the stat, £3.99 for sealant (another item currently in storage) and £8.99 for the marmalade thermometer =£18.97 ($29). The wife has already requisitioned the thermometer and I have also had to give her back her washing up bowl (radiator water), saucepan (hot water for calibration) and measuring jug (refilling radiator). Steve |
| Steve Gyles |
| Hi Steve, Glad you've got it all sorted - this brings to mind something I read, maybe on this forum, a year or two ago - the best fix for all this worry over engine temperatures is - gaffer tape - stuck firmly over the temp. gauge! |
| Cam Cunningham |
| Steve, on the strength of your findings with your gauge, I decided to check mine against a similar cooking thermometer (Boots). My gauge reads 10 degrees F high! So it would appear that I am not as hot as I thought I was. I took the bezel off my gauge (and yes Steve it is tricky), but a couldn't seem to get the needle off. In the end I chickened out, I really didn't want to break it, so I put it back together still reading 10 degrees high. I have come to the conclusion that these temperature gauges are worse than no gauge at all! You know you've got trouble when steam comes out. If you've got coolant in the system, the needle is somewhere on the water temperature scale and the engine is running fine, I don't think there is anything to worry about. Cam, you are right! |
| Lindsay Sampford |
| Lindsay I finally got the grip I needed to twist the bezel by wearing those throwaway plastic gloves (£1 for 20 in Poundland). Getting the needle off was the easiest part for me. I placed the nails of both index fingers behind the needle hub, with the back of both index fingers resting on the dial casing and then just levered. Came straight off. It was a few trial and error replacements to get the reading right. It was surprising how quickly the water temperature dropped. It was a bit of a race from the engine to the cockpit to get the needle back on before the temperature dropped a couple of degrees. It would have been easier to have 2 people involved; one calling out the readings while the other fiddled with the needle. At least with your system you have 2 sensors controlling your temperature, so the gauge is almost superfluous. Steve |
| Steve Gyles |
| Glad you've cracked it at last Steve. Funny thing - I've had three temp/oil gauges on mine over the years and they have all read similar w/temp and o/pressure readings. I now work on the assumption that the gauge is fine and that fixed grin remains as those two little needles sit around where I'm used to them. Pete |
| Pete Tipping |
| Pete Mine was new 13 years ago and I always believed it was accurate (fixed grin). Lindsay also had a fixed grin until today! Are you SURE yours is reading correctly? 3 units from the same supplier/manufacturer, using the same jigs and checking equipment could all have the same errors. Remember what I said about periodic calibration, it applies to manufacturers as well as DIY engineers. Steve |
| Steve Gyles |
| Steve, my grin is even broader because I now know that whatever my temperature gauge says, I am ten degrees cooler. I suppose it's a bit like wearing a watch that is five minutes fast. I am now starting to wonder if my oil pressure gauge is reading ten lbs high! Arrrrgh! |
| Lindsay Sampford |
| Lindsay Now I know how to do it I might set mine 30F too high just to scare passengers. A quick fix on the speedo should see me doing 110mph, perhaps at 3500rpm. Now to fix that fuel gauge for cost free motoring...... Steve |
| Steve Gyles |
| One day years ago I intentionally redirected the temperature needle on my 220dF gauge to read 185dF on a hot day. For five years lots of people were regularly begging me to tell them how I managed to have such a cool running MGA. That sure took the edge off of a lot of arguments. Since then I put the needle back where it belongs and try to be open and honest about the ordinary nature of these cars. I've never had any engine damage from overheating, just cranky carburetors that don't like alcohol bubbles in the hot fuel. I had an evil premonition last night. I drempt that we all got together and solved Dominick's over-cooling problem, and now he's PO'd at the lot of us because his MG now over-heats like everyone else's in warm weather. |
| Barney Gaylord |
| I was in the Watford MG Breakers yesterday and picked up a handful of thermostat gaskets and an 88C thermostat. Just wondering if it's worth the effort replacing the 82C stat I fitted last week (read above)? Steve |
| Steve Gyles |
| I think The King of Cool is addicted to heat! Go for it Steve, you know you want to, think of those warm toes you're going to have! |
| Lindsay Sampford |
| Well having suffered for years from over cooked roast beef and really well done steaks when I much prefer medium, I decided last year to invest in a digital meat thermometer from Maplins. It has a metal probe approx 5" long and using it has improved my cooking skills amazingly. It has a range of -30 deg C to +300 deg C and I have checked its accuracy in both boiling water and in ice and it is absolutely spot on. I used it to check the radiator water temp as my gauge showed only 100 deg F even though the engine was up to full working temperature. The digital thermometer indicated 80 deg C which proved that my gauge must be wrong. When we checked the gauge we found that the glass had slipped slightly and was preventing the needle from moving fully. Once we fixed this, the gauge then moved up to 175 degF (which almost exactly 80 deg C) So Im fairly sure the indicated 165 degrees F that is the temp that my gauge now usually shows since I fitted the larger diam plastic fan, is correct. So I have a "cool" car!! There are however a couple of downsides to this! I recently used the thermometer to check the temperature of my 3 month old grandaughters bath water as my daughter didnt trust her elbow for the task. ( for those who like technical details, 34 degC is recommended apparently) The Downsides? Well my freshly bathed grandaughter and the medium cooked steaks both now have a slight antifreeze aroma to them! But the MGA radiator has a more worrying mix of beef and baby oil!! Maybe Steves marmalade thermometer would have been the better option after all! Colyn |
| Colyn Firth |
| Colyn Most amusing. Now I know what the funny taste was in my Ovaltine. I have always wondered about giving my car a name, perhaps now I could call it Marmaduke! Steve |
| Steve Gyles |
| Colyn why get all technical about babies bath water. Simple check is, if the baby turns blue the water is to cold and if baby turns red it is too hot. Always worked for me! .. Sean |
| S Sherry |
This thread was discussed between 10/12/2010 and 26/12/2010
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