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MG TD TF 1500 - Thermostat for a 52 TD (overheating)

Hi all,

I just picked up a 52 MGTD, Seems to run well! I took it for a drive the other day and pulled a hill and it overheated and I lost power. I got it home and to my surprise there was no thermostat in the car.

I also checked the timing to make sure it was within spec and all was ok!

Where can I find a new thermosate for the TD?

Thanks,
Sal
SL Salvatore

if there is no thermostat and your car overheated, did the last owner remove the thermostat in a failed attempt to cure an over heat problem? as you may know, a missing thermostat is not healthy for a properly running engine, but it should not CAUSE the engine to overheat.
i think you may need to find out what cause the engine to overheat which the previous owner tried to fix by removing the thermostst. regards, tom
tom peterson

I have no idea as the orig owner has passed away! This vehicle was in storage for a few years before i picked it up!

-Sal
SL Salvatore

The missing thermostat is not your problem, as mentioned....Chances are, either the cooling system is not operating correctly, or there is head-gasket damage.....
First , check the plugs for signs of burned coolant....Although burning coolant will usually show up as white smoke in the exhaust, it isn't always obvious....
Also, are the plugs the correct color (light tan on the porcelain), or stark white?....You checked the timing, but the dizzy (or coil), may be breaking down under load.
After the plug check, do a compression test, while the engine is warm...This may show a variety of problems, that could lead to overheating.
Also, make sure your water pump is actually circulating coolant, by observing the flow, with the car running and the cap removed.
If all o.k., then flush the cooling system , or consider having the radiator professionally "rodded" out, and cleaned.
Edward
E.B. Wesson

The car will not overheat if not under load, plan flat road driving. it will only over heat when going up a hill or under load.

-Sal
SL Salvatore

Sal,

In addtion to the other suggestions:

Oil the advance weights in the distributor. A lack of advance will cause the symptoms you are seeing. The timing should be set so that you can see about an 'inch' of advance with a strobe timing light at about 3500 RPM. Sometimes the lock screw in the center of the points cam will lock the advance plate. Insert it with a thread locking compound, then back off a turn and let dry.

warmly,
Dave
Dave Braun

One of the best things to do is send the distributor to Jeff Schlemmer at Advanced Distributor, who will put it in tip-top shape, and will allow you to dismiss the distributor as a (very real) possible cause of the problems. When I had a Mustang repair shop in CA, we found that the majority of overheating problems were related to bad or badly-adjusted vacuum advance units. Ironic that cooling problems (like carb problems) are often electrical!

Check your core plugs; you may find one of more leaking or rusting. If so, you will probably find lots of rust and crud blocking cooling passages in the engine, another real cause of overheating. Also, the two holes in the outer galley passages may be plugged, which makes a difference (see the archives).

I sell brass core plugs guaranteed never to rust or corrode.

Tom
t lange

sal, if you are not familiar with the XPAG engies, my experience has been 100 F temps..up hills, steep grades, etc. the temps sit right in the middle to lower end of normal range. if i sit and idle of an EXTENDED period of time in those temps the engine coolant temp will climb. i have never had an over heat.
i did boil out the block and radiator when i did the engine a few years ago.
the guys here are spot on with their suggestions. regards, tom
tom peterson

Sal, To answer your original inquiry, an "orginal" thermostat with sleeve is listed for sale at Abingdon Spares for $80.34, item # 07 035. Moss also sells a look-a-like aluminum housing which can take a modern thermostat, which is what I installed in my TD and has worked well. (see image) With the modern housing and thermostat, it is also recommended to fabricate a blanking plate with a 3/16" hole drilled in it to compensate for the missing sliding sleeve which was found on the original thermostat (see image 2). It's all explained in the archives as well. I would not recommend driving the car without a thermostat, as some believe that the car could actually overheat, due to the coolant passing through the rad too quickly without the resistance of a thermostat, and not being able to dissipate the heat as efficiently. If you are handy, you might be able to retrofit a modern thermostat at the top of the original cast iron housing, after removing the cross bar.You would also install the blanking plate. This would be the least expensive way to go. Cheers Phil


Phil Atrill

Image 2


Phil Atrill

Moss's aluminum thermostat housing is not a great idea; the housing starts corroding (eroding?) almost immediately, into white dust. There's lots in the archives about modifying the existing iron housing to accommodate a modern thermostat, which is a better way to go.

Tom
t lange

See http://www.ttalk.info/modern_thermostat.htm for installing a modern thermostat into a TD. Bud
Bud Krueger (TD10855)

Sal,
Unless your MG has a heater, you really don't need a thermostat, and it will actually work better without, as long as the bypass is blocked. Installing a late model stat is not difficult and has been detailed in previous posts, so if you do have a heater, you can look up the archived discussions.

I'm betting your bypass is probably wide open and that sabotages the cooling system. A significant percent of the hot coolant leaving the head is shortcircuited right back into the engine.

The remedy costs virtually nothing. First, drain a few quarts of coolant out of the system, then remove the 2 screws holding the bypass elbow to the thermostat housing. You'll probably find a gasket with a large hole in the center. Find a little sliver of material for a new gasket and cut one out with no hole in the center, only the 2 holes for the screws. Sandwich that one in in place of the original to block off the circulation down the bypass hose.

I posted a picture to illustrate the bypass elbow, but ignore that thermostat configuration, it isn't my handiwork.

By the way, running a good % of antifreeze will raise the boiling point to avoid boiling off coolant on extreme conditions. Double check your plug color for lean running... and your timing, so it isn't retarded, too.

Fill it back up, and on a hot day, charge up one of those long, tall hills in NJ, then report back with the results.




Jim Northrup

All of the above suggestions are good and should be checked first, but most overheating problems are caused by the old radiator. The only real cure is having it recored. Expensive but effective and an insurance for (further?) engine damage.
Willem vd Veer

I just drove my 52 TD in a parade. We drove for 50 minutes at walking speed and the temperature gauge went to the maximum. She cooled down when I drove it home at moderate speed.

Is it norma for the car to overheat at long slow running?

Dan Sexton
D.J. Sexton

...pretty normal I would say....basically idling along on a hot day.... that is the only time mine has approached 95C......
gblawson(gordon- TD27667)

Here was my limit from a parade with bright sunshine directly onto the radiator. The image was taken as I was considering opening the bonnet. The 50/50 mix of Prestone/water boils at about 220F. We survived. Bud


Bud Krueger (TD10855)

Drove in the Dunwoody 4th Parade today along with 5 TD's, 3 TF's, 1 MGA,i midget, and 6 MGB's. The temperature was pushing 96 F.
Ran the parade at a very slow walking pace with many stops.

My TF ran at below 85 C until the very end and then went over a "needles width" as the parade stalled entering the parking lot. This matches my 180 degree F thermostat.

I flush my radiator and use "Water Wetter" with plain water and no Antifreeze in the Summer. Decreases temp by 10 degrees C.

Some with 50-50 overheated and got up to 100 or more C.
One TF dropped out temporaily due to vapor lock. All finished.

Yes it is normal to run hotter at parade speeds since the air is not moving thru the grill. However a clean radiator and "Water Wetter" will solve most heating problems.
Don Harmer

Hmm, I do have a heater tho I do not have it hooked up, The bypass is wide open. Maybe I should try the plate with a 3/16th hole?

Thanks for all the help great great info!

-Sal
SL Salvatore

If you have a late model thermostat, there's an argument in favor of the 3/16" hole (a 1/16" hole in the thermostat would be better, though).

With no thermostat, there is no reason to have a hole and it will just reduce cooling a touch.
Jim Northrup

I agree with Don concerning the use of water wetter instead of anti-freeze, especially in the summer.

A mixture of anti-freeze and water may raise the boiling point to 220 degrees but so what? It doesn't keep your engine cooler, all it means is your engine will be 8 degrees hotter than it normally would be when you'd shut it down from boiling/overheating.

For engine cooling, less anti-freeze is better: http://www.challengers101.com/CoolantMix.html
Gene Gillam

does water wetter prevent corrosion? perhaps i over looked it. if it does not, i believe whatever small gain you get initially in cooling efficiency will be lost to increased cooling system corrosion. i'll read the water wetter info again. regards, tom
tom peterson

i see the factory info on water wetter says corrosion protection. regards, tom
tom peterson

Sal,
I'm curious,,, what was the temp gauge reading when it overheated????? I could not find that in the thread,,, Was the needle into the oil pressure side???

SPW
STEVE WINCZE

It was over the 90 mark, I cant recall where it was! lastnight i installed a thermo and the restrictor plate on the bypass. I let it idle for a bit and it went up to the 90 mark.

I took it around the block and it droped a bit. I removed the rad cap and inserted my A/C temp guage and it was at around 178.

Later today i will take it on a longer up hill drive and see what it does!

-Sal
SL Salvatore

what should be the normal reading on the guage if its accurate?
SL Salvatore

Somewhere in my reading about "T's", (maybe in the owner's handbook...don't remember), I thought it said not to run a mix in the coolant, but to run straight anti-freeze, as there would be better corrosion resistance....Am I mis-remembering?....
I have Water-Wetter + anti-freeze, and my coolant never gets above about 87C....Of course that's normal driving, not sitting in traffic.
I did add an overflow bottle, just in case there is any boil-over....It seems to work, in spite of the lack of pressurization....
Edward
E.B. Wesson

E.B.,

Yes, you misread something (I don't know what!). Straight anti-freeze does not improve cooling (actually makes it worse).

Water wetter can be added to a 50/50 mix:
http://www.redlineoil.com/content/files/tech/WaterWetter%20Tech%20Info.pdf
Gene Gillam

Ed,
Re-read that link that Gene Gillam posted. I like the idea of no coolant/antifreeze in the warm weather. Just the proper amount of Water Wetter (or similar brand).


For engine cooling, less anti-freeze is better: http://www.challengers101.com/CoolantMix.html
Mort TD 1851

...if you use water only, be sure to flush out your system once a month....took only a week or so for my water to turn brown....not, i thought, a good thing...went back to the 'normal' old mix....no probs...
gblawson(gordon- TD27667)

If you have ever studied how a GEYSER works, YOU WILL RUN ANTIFREEZE!

Water only? Drive only around bodies of water!
Jim Northrup

A few thoughts
I purchased my TD approx 10 years ago an had a cooling problem esp in 40 deg Celsius plus days in Melbourne. Stopping at traffic lights was a problem. The car had no thermostat and the bypass was fully open.
I tried the following the improve matters
1. Blocked the bypass - some improvement
2. Added water wetter after a system flush - some improvement
3. Drilled the small hole in the block behind the front plug - No noticeable change
4. Had the radiator rodded - no improvement.
One day arriving home I got out of the car and could hear water trickling, it was the radiator. At this point the light in my head turned on. The radiator core was restricting the flow and the lower tank had vapour/air in it and there was a possiblity of the pump suction having the same. The water flow would have been effected as well.
I then had the radiator recored with as many rows of tubes as possible. Problem solved!
In thinking back to my process engineering days we are basically operating two interconnected heat exchangers.
Perfomance is improved by;
1. As high a flow of coolant as possible without causing the problem I mention above. As it is an unpressurized system the pump can only suck water through from the radiator which can cause the water to boil at less than 100 deg.
2. Anti freeze has pluses and minuses. It raises the boiling point however it lowers the Specific heat of the coolant - you need more flow for every joule/BTU that you remove. It also increases the viscosity which could reduce the turbulence at the surfaces and increase the resistance to heat flow
3. Anti corrosion additives are good as corrosion on the surfaces also increases resistance to heat flow. Water wetter helps by getting rid of micro bubbles on the surfaces.
I am not a fan of adding overflow bottles as I believe TD upper tank has a built in one by being so large.
A J Clapham

This thread was discussed between 01/07/2011 and 07/07/2011

MG TD TF 1500 index

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