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TR2/3/3A Overheating Problem

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BobbyO

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I'm sure this has been discussed several times before; however, I couldn't find a close enough duplicate. Rebuilt engine (around 1990 but not started until recently), radiator flushed by radiator shop but not roded, warm to the touch throughout after running, thermostat checked and operating as advertised (185*), pressure cap new from Moss, 4 psi. After about 200 miles and a 50 mile road trip engine overheated while idling (to the extent it blew coolant through cap). Allowed it to cool, replaced lost coolant and started the 50 mile return home. The engine continued to run hot, around 190* - 200* when moving but overheated again when caught in town traffic. Allowed to cool again, replaced coolant and made it home. Pulled into garage with temp indicating around 200*. When shut off engine temperature went to peg and blew coolant. The next day, started engine, allowed temp to reach about 190*, shut off engine and same thing happened.

Now, after all that, my question is: Where should I go to determine the cause and obtain a solution? I would prefer to not have to remove the radiator since I just got the car on the road and have only about 250 miles on it. But, of course, if I have to I'll do it. Everything was normal for the first 200 miles.
 
All of your symptoms are typical and get worse as the air temperature increases. The extent to which the heating of your occurs is not typical, however. First thing I'd look at would be the radiator. A good radiator shop will check the radiator flow. I wonder if your shop did that. Since these cars tend to do all the things yours did, but to a lesser degree, there is little margin. A ten or twenty percent loss in flow could cause your issues.
A couple of other things to rule out would be a combustion leak (any good shop can do this or you can get a kit from an auto supply). Finally, check the ignition timing, badly retarded timing can cause overheating too. Less likely but certainly possible, would be a bad water pump impeller. Sorry for all the options, perhaps some will narrow down the cause.
Tom
 
I don't think it's unusual for a freshly rebuilt engine to run a little warm for the first few thousand miles or so. It seems many of us have had issues with overheating. But also don't confuse a little coolant puking out of the overflow of a warm engine with over heating. These cars were built prior to the use of 'overflow' or 'catch' bottles. Our cars were expected to blow a little out on occasion. The level of fluid in the radiator should not be filled to the top -there should be a little air at the top of the filler neck so that you can just see the coolant at the bottom of the neck. If I were you, I'd try to avoid driving in traffic until the engine is more broken in. Actually, even after the engine is broken in, I still try to avoid driving in traffic. But, since I too have seen my temperature rise, I added an electric fan, after I was sure everything else was in order, including timing/advance/carburetor adjustments/coolant flow.

Good luck, enjoy.
 
Might bump your cap up to 7 psi and see if that helps.
 
I would suggest that the radiator is a little plugged. They need to be re-cord or rodded out; it sounds like the gauge is at least accurate. In addition, get a different fan set up if you are using stock. That Macy’s fan looks like it should do the job. I have not tried one, but I do have a tropical fan and it made a big difference, and the Macy’s fan looks similar, plus Macy made the fan just for your problem.
 
I replaced my radiator at the same time as installing Macy's fan and only occasionally am a tick above the 185 degree level. Not sure what actually fixed the overheating problem, but I was in bumper to bumper traffic this Sunday with the outside temperature at 93 degrees and the temp stayed constant (just over 185) until I got moving and it remained just below 185. I feel the Macy's fan was one of the best investments I've made.
 
I installed an overflow bottle, installed an electric fan, removed the stock fan and have had no overheating problems since. I've had it in parades with no heating problems. Your radiator may be a little plugged; but you have to remember the temperatures in England didn't get as high as they did in the midwest and lower part of the U.S..
 
I use a re-cored radiator, air dam, TR tropical fan, recored radiator (with crank hole) and a mostly blocked bypass. I also replaced the liners awhile back which let me clean the coolant jacket area well.

I don't what helps and what doesn't but the net result is no overheating in 100°+ days.

An IR thermometer can be used to good advantage in diagnosing a clogged or otherwise faulty radiator - also for comparing temperatures of various engine locations.

I have never used a 7# cap for fear of straining the system - e.g. not sure my heater would like it. I tried a recovery bottle but the TR# cap (at least mine) would not draw coolant back in.

Of course you do not want to overfill the neck - that will cause puking even in normal operation. I fill mine until I can just see the bottom of the neck is wet.

I suspect the biggest single improvement is a better fan - if a tropical fan is not available then the Macy unit looks pretty good.
 
Just a side note. I saw on the news yesterday that the temperature at Palm Springs was 121 degrees, I don't know if any of these cars could handle that; in fact just touching the body if it was setting in the sun would probably give you a good burn.
 
My wife said she saw on the news this morning that they measured the temperature inside a car in AZ and it was 161 degrees....crazy temperature!
 
Not the plastic - but a 6-bladed metal fan:

Tropical2_zps04e63f76.jpg


But the yellow plastic (TR6) is also superior to the original TR3 fan.
 
I hope outside air temperature was my only problem. Checked back and the high that day was around 98 which was probably the temperature on the initial ride out. A couple of thunderstorm passed while waiting in a garage so the temp on the return most likely was in the high 80s, low 90s. Anyway, I've verified the thermostat is working correctly, the fluid level is correct (If I remember correctly, the shop manual says 1/4 inch showing in the filler neck. That's about what I have.) Re-torqued the head to minimize the possibility of a combustion leak and checked timing and mixture. Is there anything I've missed? Tomorrow, early, I plan to take a short trip to see how things go. If temps are reasonably normal I'll invest in a fan. Don't want to do that until I'm sure the radiator doesn't have to come out. Should it need to come out a new fan would be much easier to install at that time. Thanks for all the suggestions/help.
 
I got caught in 117 degree heat one day coming home from a car show in a stock TR3. Inside the open compartment of the car in front ( a TR4) of me the guy had an IR gauge that said 120. The car did a lot better than the driver and passenger. The thing that really surprised me was that the radiator temperature actually went down slightly from about 190-195 after I got off the freeway and onto the city streets. They can take it if they are properly tuned. Prior to this day I had a lot of overheating. I finally found the problem was the choke connection rod under the cabs was causing the front carb to run to rich. Found the problem with a Colortune unit.
Charley
 
I've told the story before but will repeat it here: One summer day I drove the TR3 past one of those time/temperature displays and thought 'It seems later than a quarter after one'. Then the display changed to 2:30 and I realized that the 115 I saw wasn't the time.

Like Charley says, the limiting factor is how much heat the driver can stand.
 
Feel I've got to add my stories.
It's July 1967, just graduated from high school. Four buddies, two in my '61 TR3 and two in a 67 MGB head out from Pennsylvania with the destination, Ft Lauderdale, Florida. My TR3 was in very good shape with the odometer in the upper 30 thousand mile range. Florida was solid in the high 80's to mid 90's each day. The TR3 never overheated nor skipped a beat.
It's July 2001, just got the TR4A's engine rebuilt. Drove it home some 30 miles...she ran hot the whole way. When parked the water pumped out of the overflow bottle. Was told this could happen for awhile with a new rebuild, but the problem continued to a point where I just couldn't stand it. I removed the radiator and dropped it off at a radiator shop. The radiator folks called the next day saying in their words "it's junk". They rebuilt it re-using only the top and the bottom. Everything in between was replaced. The TR4A hasn't overheated since.
 
Is there an electric fan that can be installed in front of the radiator to assist with air movement and run after the engine has been shut down? Leaving the mechanical fan in place.

David
 
David: Nothing will fit in front of the radiator. You can do a few things, run the TR tropical fan (if you can find one), but a yellow fan and mount it backwards to fit, run a TR6 red fan, install a puller electric fan and delete the TR3 fan all together.
 
carpecursusII said:
David: Nothing will fit in front of the radiator...
Click to expand...

Not true. Many are running a TR3 with a pusher fan. You'll have to take the apron off of course to mount it and you may have to trim the cardboard air deflector.

Here's Don Elliott's set-up. He's using a 12" Kenlowe. There are many others that will fit.

FanElectricPusher.jpg
 
For many years I used electric pusher fans on the front of the radiators to help the stock fans.

The fan I used:

fan_zpsa02eb36b.jpg


Had to oblong the holes in the mounting tabs to match the width of the radiator:

fan7_zpsdd60df96.jpg


Used decapitated bolts bent into ells:

fan1_zpsca3977a6.jpg


Bits of fuel line cushioned the fittings:

fan2_zps61b464dd.jpg


Here it is in place:

fan8_zpsd3fefc22.jpg


Wired the hot side to the horn circuit, the ground side to a switch under the dash. Used it for many years w/o problem - just flipped it on when I saw traffic would be slow or when I was starting up the mountain on a hot day.

For the TR3 I had to remove the grille for the install - for the TR4 had to remove the fibreboard duct. Both go back on afterwards of course.
 
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