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MG MGA - Airflow through radiator - mesh supplier?
|My A reaches 212 degrees when on the motorway on a warm day at a steady 60 mph. I have done the usual - thoroughly flushed it out, new thermostat, water pump, recored radiator, etc. But I had an idea so took her for a drive today after removing the radiator grill, and there was a very marked improvement.|
I know some owners have twisted the grill slats to let more air in (I have a Mk2 so different grill to most) but I was hoping to be a bit more drastic than that.
I was wondering if anyone has a source for a mesh grill, or even better just the mesh itself? I have seen http://www.clarkandclarkinc.com/1192_meshgrille.htm but was hoping to find something in the UK. I think they look rather smart and really its only a case of finding just the stainless steel mesh itself and it should then be a very simple case of fitting to the existing grill frame.
And has anyone considered a brilliant but simple idea from Ian Cowan in OZ ?http://mgaguru.com/mgtech/cooling/cool_209.htm
I tried this as an experiment. I bought a piece of Stainless mesh on e-bay from a UK seller, cut it to suit and bowed it as required. I secured it using the same fixings as are used to secure the grill slats top and bottom aluminium strips. It dropped the engine temperature by 10 degrees. After i put the slats back in, I also made up some blanking plates to close off the area either side of the top of the radiator and the front scuttle so as to close what, for the small area involved, amounted to 6 sq inches.
|Graham, I purchased a stainless steel mesh grill from Lockwood International (Leeds, West Yorkshire) for my RX-8; they have absolutely top quality materials. They have cut to size for specific car models as well as do-it-yourself material in varying sizes. Here's their site:|
|Moss sell the sets....at least Moss USA do.|
|I hate to rain on the parade, but having a mesh grille I can't support the claims that it lowers temperatures against a standard grill with the slats lightly opened up. I recently installed a new grille, and put an old standard one in place while waiting for the chroming of the shell. Putting the mesh grill back on the car resulted in no temperature change at all. It does look better with a mesh grille!|
You are talking about putting a plaster over the symptoms instead of an operation to remove the cause. At 60 on motorway type roads in these summer temps my car sits at 175 and that with the 1800 engine.
I will put money on your recored radiator being to the wrong specification for the MGA.
|I'm with Dominic and Steve. Basically, if an MGA overheats, particularly merely in the UK, there is a problem, and radiator grill mods are almost certainly not it. |
|I agree with Dominic, Steve, and Bruce.|
Your engine shouldn't get that hot here in the UK, I was out yesterday in temperatures of about 25 degrees C and my temp gauge was showing between 175 and 185 degrees F whilst the car was on the move.
I run with twin electric fans instead of the engine driven fan and the temp will rapidly climb up to 212 degrees when the car is stationary, but then the electric fans come on and quickly bring it down to 90 degrees and switch off again.
Once the car is back on the move the temp goes back down to around the 180 mark.
(Bear in mind that your radiator will not boil over until it goes over approx 130 degrees)
So I would look first at your radiator, see if you can borrow one that is known to work ok and try it out.
On the subject of radiator grilles, I opened up the slats on my repro grille last summer to see what effect it would have and it did reduce the engine temp by about 5 degrees F and so it was definitely worth doing.
|I also agree|
You have a problem that has got nothing to do with your grille
What thermostat are you running, If it's too high the radiator hasn't got a chance of keeping temperature under control
For an MGA it should be 160-165f or 70-75c
This is the temp that the thermostat STARTS to open and should run around 170-175-180 on the gauge with one of these
What temp rating is yours ??????
Colyn made the very sensible comment about borrowing a known 'cool' radiator to see what difference it makes. I once did that for my near neighbour and he was startled by the difference. He had tried everything else including an electric fan and oil cooler.
In the next few months (sometime after September I suspect) I am going to be laying my car up while I effect some bodywork renovation. I am also intending to remove the radiator at the same time for a repaint. I would be more than happy to lend it to you for a trial if that helps. I frequently come up the Middlesex direction to Mill Hill so can always drop it off.
Have you got the 2 pieces of air duct hose in place forward of the radiator to stop the air going round rather than through the rad. Also the felt / foam strip on the bonnet to stop air going over.
|A J Dee|
|Just to emphasize the effect of a bad radiator,,,,, a couple of years ago I put a new engine into another A and at the same time replaced the old radiator with a brand new Moss one. The cart boiled, and nothing I could try had any effect at all, until we threw in an OLD and terrible looking original one that was bought on eBay for ten euros. Instant results. |
Having a high efficiency core is apparently not the answer. One of the midget BUBS guys uses cheap brand coca cola overnight in the cooling syste,m followed by a flush to remove the crap., maybe that is worth a try....
Thanks for all the very helpful posts. Really interesting and useful. Of course I can only agree that I shouldn't have to change the grill to solve the cooling issue, but when you think you have tried all the obvious things and it works, its hard to ignore!
I now find on street driving I am at a steady 190 degrees and on my "faster test run" over 10 miles on M25 at a constant 60mph, it gets up to 200d and stays there. Very acceptable for me compared to what I was experiencing before the work on the cooling system.
As I sadly dont have a 5 speed (yet) my revs are probably higher than some other cars (3500rpm for 60mph).
I do like the look of the mesh grill so may well go for it regardless, especially as its so easily reversable.
Steve, that is an exceptionally kind offer and I would be mad not to take you up on it. I am very happy to come to you, or am only 5 minutes from J17 of M25, if you are travelling to Mill Hill.
Incidentally I do have the felt over the rad space and air duct hoses. My thermostat opens at 180d
Thermostat opening at 180-------
I'm thinking that is causing , or possibly causing the hot problem
160-165----------worth a try
I will come back to you when I start my work. The same offer is there towards the end of the year to any other 'overheaters' in my vicinity.
At the risk of upsetting the purists, who I must admit make a very good point (but until I try another radiator, I am out of ideas) can you explain exactly how you fitted the mesh without snapping out the slats from the inner frame.
On my car the inner frame to which the slats are riveted also has riveted to it, the upper brackets with welded nuts for installing in the car. Did you fabricate a new internal frame to secure the mesh, which also had brackets for fitting to the car?
Thanks. Let's hope I have it sorted by then! - I adjusted timing that did make a marginal improvement.
I am thinking I should treat myself to a 5 speed box. That would bring the revs down a bit.
Pretty sure it's not the thermostat. After I bring the speed down to say 35 mph, the temperature soon comes down as well.
I had a spare set of slats and their aluminium strips with the fastenings attached. I drilled out the rivets of the slats and simply fastened the mesh between the grill frame and the aluminium (Having bowed it in two planes to get the curve right). I used the original fixings still fastened to the top and bottom strips. Sadly i didn't get a photo to show the internals.
Reading back through the posts, it does sound like the radiator could be suspect and not up to the job under load, but--
I put to you that with the thermostat that you have being 180 deg, your whole system is running 20deg higher than it should be and the radiator doesn't get a chance to cool the water off enough as it's entering the radiator 20deg higher than it should be to start with
Out on the highway, yes you get more airflow but the coolant is also flowing through the radiator faster because of the extra engine revs and this is when the radiator doesn't get time to cool off the super heated water
It would really be worth trying a 160 -just out of interest to see what happens
Thanks. Ah yes with a spare set of slats to play around with, I can see how you did it. I don't really want to drill out the retaining rivets from mine as I'm just trying it out, and want something that's easily reversible.
Also as I have a Mk2, I think it's a bit more tricky because of the way the grill is recessed at the bottom.
I guess I need to make a new internal frame. I'm not too bothered about fixing the new mesh but the angled fixing points for the top need to be properly attached to something.
It can be done but was hoping there was an easy short cut I'd missed!
Thanks for the post. We were obviously posting at similar times so I didn't notice it earlier.
Yes your right it's simple enough to try a different thermostat but I am struggling to understand the logic. I understand that initially the rad is being allowed to start its work earlier, but once the car has been running for an extensive time, I Dont understand what difference it will make?
|Graham, If the only symptom of your problem is the temperature gauge reading 212 degF (and the gauge is accurate) then maybe you don't have a problem at all.|
Because you still have 20-30 degrees in hand before you reach coolant boiling and if you don't get the dreaded vapour lock then I wouldn't worry.
Going along at 60mph on a warm (temperature?) day is close to being flat out and your situation is not likely to get much worse.
I agree with you that changing to a summer thermostat shouldn't make any difference when the coolant is at 212 F because both hot and cold thermostats should be fully open at this temperature anyway and not affecting anything unless perhaps there is a problem with your own thermostat and it isn't fully opening at 212 F. Out of curiosity you could always try removing the thermostat completely to see if this makes a difference. ....................Mike
Interesting comments and good points you make. Thanks.
I don't think there is a problem with the thermostat. It is new, that's no guarantee I know but I clearly "see" it open as the temperature builds up from a cold start, and then suddenly drops when it opens and the cold water rushes through.
I didn't realise the buffer before reaching boiling point was as much as 20 - 30 degrees above 212. I have a 4lbs radiator cap. Do you think I should change to a 7lb? In particular are there any downsides, such as more chance of leaks?
|Graham, I was assuming you would have a 7lb cap plus a goodly percentage of antifreeze in the coolant. A 7lb cap wouldn't affect any of your temperature observations but it would give you more peace of mind when you see the gauge at 212!...............Mike|
My Mk 2 Coupe runs at 160-180 on a warm day at a steady 70 on fast roads - as you know I have the 5 speed gearbox so revs are lower than yours my engine is the 1622 with a slightly higher comp head.
Last week out at 33 degree ambient temp my guage did hit 190!in traffic
some two years back I was getting higher temps but careful tuning of timing & mixture helped bring it down- I have the standard possibly original (recored?) radiator and the grill slats have not been widened
|P D Camp|
I agree both thermostats, when fully open would have the same loss of temperature control which would point towards a radiator problem or as Paul mentions maybe engine tune--something like a seized mechanical advance in the dizzy can be easily overlooked and cause high temps
My thinking on the lower thermostat was/is that by starting at a lower temp opening point it might just be enough to stop your whole cooling system getting to the point where it is out of control
With boiling points, it's usually 1deg for each lb
7lb cap 219deg
But really you should have figures like Paul and never get over 190deg which would be almost impossible with your thermostat of 180deg starting point
I'd almost put money on Paul's thermostat being a 160
|Willy, Water boiling point is raised 3 degF for every 1 psi above atmospheric pressure so a 7lb cap would give a 21 degF rise. However, if you've got an ethylene glycol antifreeze mix as a coolant of around 40-50% you can add another 5-10 degF to this giving a boiling point rise of about 25-30 degF to 242 F max....................Mike|
|Just my 2c worth to stir the pot - mine never gets above 170, even in summer Ontario. Yes the gauge is accurate as tested in boiling water. I have the original radiator. I was thinking of changing the thermostat as I think this is too cold. It also warms up very quickly, about 3 mins.|
|I understand the general consensus is I should try a different radiator which I would like to do, but interestingly, it does seem, as Paul intimated, we are not always necessarilly comparing like with like. From the archives, I see Steve G's 1800cc travels at 60mph on 2550rpm. Mine needs to turn at 3500rpm for the same speed.|
I have been on country roads today and the gauge never went over 190 degrees, but then the mph rarely exceeded 50mph (about 3000rpm in 4th)
SO THE REAL ANSWER is I need to convert to a 5 speed box!! :):) Joking aside, it's something I have often thought about - maybe this winter?
Mike, I will definitely change my cap to 7psi so thanks as I will certainly feel more relaxed if/when the guage hits 212 degrees.
PS Still tempted to go with the mesh grill
I altered the angle of my slats from day one and saw a small decrease in temperature.
Ref the slat/mesh fastening to the grill frame, you can easily make up the strips to secure the mesh to the grill fixings; some aluminium rectangular bar from B&Q will work. You would have to drill out the rivets securing the brackets (not the slats) to the existing strips so you can use them, and they can easily be riveted back in place to return to original.
My mesh took at least 10 degrees off the temperature.
Yep ,I stuffed up with the temp/pressure calcs there sorry about that. We're on deg.C here and I got mixed up in my conversions
I still can't see the logic behind making your car so that it can go to 230deg. without boiling when really it shouldn't be over 180 ish
If it was running straight alcohol fuel yes there is a power advantage at higher temps but for a road going petrol powered car I'm having trouble understanding why
Difficult one to call about speeds/rpm for stabilised temperatures. Whilst of course I am at lower rpms for any given speed, I normally sit at between 70 - 80 on the motorways, so I am doing your sort of rpms but of course also have a greater airflow hitting the front end.
I can only harp back to my often repeated story of when I lent my radiator to a colleague with an overheating 1500. My radiator made up to 30 degrees of difference to his car. He immediately went off to Bob west, changed his rad and never looked back.
I bet you are correct that my thermostat is a 160 I have never looked at it in the 8 years I have owned the car - but it warms up very quickly and I can see on the temp guage that it opens up around 165 ( that's when the temp falls back a bit) and quickly settles at 160-170
|P D Camp|
|At the risk of upsetting most of the people in the room, I attach a pic of my new grill.|
Thanks to Colin Manley for the encouragement and to Nick K for recommending Lockwood.
I realise that most others will disapprove and I completely undersatand the reasons, but I like the look which is obviously very simple to reverse. And if it is getting me 10 degrees of the temperature gauge, why should I worry!
|Putting aside the reason for installing a mesh over the slats I think it looks really good and suits the Mk2 really well.|
|Nice looking. I think it's better with that grill than the 1500. Steve|
|So does it work as you expected? Did it bring your engine temp down? |
|Mesh grille looks good on a 1500 also!
|Thanks for the feedback. |
I haven't properly tested it yet as I am waiting for the ambient temeprature to go up a bit first.
But based on tests with no grill at all, I am cautiously optimistic. I will report back when summer resumes!
Today is the first warmish day since I fitted it. Ambient temperature 24 degrees. So I took her for a quick 15 mile spin at 60 mph and was pleased to find the dial never went much above 200F which is very good for me.
I also noticed a marked improvement when coming off the motorway into slow moving traffic. The temperature would always struggle if I was only moving slowly in traffic, but today I noticed a definite improvement. The radiator is clearly finding it easier to breathe with the new mesh grill.
On my car, the Mk2 grill is almost certainly not original, and it is possible that an original grill, or one from another manufacturer would behave better.
I too have been for an hour drive in today's warmish conditions, on dual carriageways and then crawling through Aldershot. 175 at 60 to 70, then 180 to 185 in the crawling stop and start traffic. So while you have noticed some improvement with your mesh (and it looks good) I still think you have a basic problem to resolve.
|You are probably right Steve. But other than a different type of rad, I am out of ideas. |
I may sell my frogeye, and if I do that I will definitely invest in a 5 speed box.
Incidentally Steve, do you have a thermostat? My car can't physically run at those low temperatures at present anyway as the thermostat would close at about 185 I think
|Same here Graham,|
Yesterday (Wednesday), we took a fast 80 mile run up to RAF Conningsby to see the Battle of Britain Memorial Flight) (a brilliant place to visit by the way). We used mostly B roads and lots of throttle but the running temp still stayed down around the 175/185 mark even in the warm ambient temperature of around 77 degrees F.
So I would definitely take up Steves offer of a temporary loan of his rad to see what difference it makes to your car.
I think you will be surprised.
PS Thanks for the tip off about the stainless steel mesh supplier, a great price. I have just ordered some to fit to my oil cooler vent which I have made in the front valence
This thread was discussed between 29/06/2015 and 16/07/2015
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