overheating

[TomFromStLouis]

I am having trouble keeping my engine temperature under 210* after sitting in traffic for more than 5 minutes or so. Once there, she sputters a bit and dies. This even occurred on a under 60* morning a week or so back. Now that it is 80*, the problem is more acute.

This has been an issue for some time. My initial response last year was to replace the thermostat; no change. Increasing idle speed seems to buy some time. It has been suggested to me that perhaps my radiator has a blockage of some degree. How would I check this? Would this be my problem if temps reduce when driving? The fan works.

I am open to brain storms.

 

[GregW]

Hi Tom,
First questions I have would be; how old is the radiator? Also, has the engine ever been rebuilt? If you've mentioned that in a previous post, sorry, I couldn't remember.

 

[Keoke]

Well Tom, These old cars with original radiators and fans seem to run hot in a hot climate. suggested methods to cool them down is :

1]Have the radiator recored with a 4 row serpentine core
2]Have the engine cooling system professionally power back flushed.
3] Hang that cute bow tie fan up ina garage as an artifact

and replace it with a:
A] 6 Bladed Texas Cooler Fan.
B] A SS 6 Bladed fan from BCS
C] Uprated cooling fans from other sources.

Failing to implement these changes probably means , driving on the back roads only in the winter and staying out of traffic.--Keoke- :laugh:

 

[anthony7777]

ya, ya, everything my friend keoke says, and gregw as usual brings up a good point about an engine rebuild, i also had a similar overheating problem, when i went to my engine rebuilder to see how things were getting along he handed me a 2/3 full 5 gal. bucket of what can only be described as "swamp mung" that had been steamed out of the engine block, not the outside of the motor or any other parts, and that didnt include what remained in the solution soak tank, ran it on a dyno, it is so-so cool.

 

[TomFromStLouis]

Some additional facts:

The car was restored in 2001, roughly 15,000 miles ago. The former owner/restorer had the radiator re-cored and many engine bits replaced (although pistons were kept). Sounds like everything was reviewed at least. The fan is one of those 3 or 4 blade yellow ones.

I drove the car today for over an hour in 80+ degree sunshine without problem, but I also avoided traffic. I still think I have a problem because of that event in 55 degree weather after ten minutes idling. Seems to me that should not happen if some of these more obvious things have been dealt with.

I hate to resurrect a fairly useless thread that amply illustrates how little I understand, but this goes back to the thread entitled "sticky floats": https://www.britishcarforum.com/bcforum/ubbthreads.php/topics/442960/sticky_floats#Post442960 In that thread healeynut suggested worn throttle bushes would give the symptoms I have. As things heat up, air leaks into the mix and starves the engine. A local MG mechanic said a similar thing even though the throttle shaft wiggles very little and the carbs were rebuilt in the restoration ~15,000 miles ago. His temporary fix was to increase my idle speed; I have not rebuilt the carbs yet. I guess I will if y'all think it is most likely the real problem.

 

[healeynut]

Tom -

Keoke got's most of the stuff covered... a few other thoughts...

If you car gets really hot and dies, then it can also be from fuel starvation as the fuel can boil in the float bowls. Other than getting the engine to run cooler, the best solution for this problem is to have your exhaust headers jet-hot coated, but this is a job best left for engine/carb rebuild, clutch replacement or exhaust pipe replacement time.

When you replaced your thermostat, did you replace it with a 180 deg or 190 deg Tstat?

If so, put in a 160 deg T stat, that should help quite a bit. These cars were designed to operate at cool temperatures, so in the summer, 160 deg t-stat is a good idea. Get the sleeved 160 deg T-stat that BCS in Stockton sells - it has a wider mouth so allows more coolant to flow. Be sure to get the gasket too, to make your job easier.

 

[nevets]

ignition timing will also influence engine heating.

 

[zblu]

Keoke,
Hung my original ali prop on the wall a long time ago, mind you just for self preservation purposes
Using a 5 blade fan atm
Are the plugs the right range?

 

[GregW]

Some additional facts:

The car was restored in 2001, roughly 15,000 miles ago. The former owner/restorer had the radiator re-cored and many engine bits replaced (although pistons were kept). Sounds like everything was reviewed at least. The fan is one of those <span style="font-weight: bold">3 or 4 blade</span> yellow ones.

Regardless of the problem, I'd think about upgrading to a better fan like what Keoke mentioned in "A" or "B"

As things heat up, air leaks into the mix and starves the engine. A local MG mechanic said a similar thing even though the throttle shaft wiggles very little and the <span style="font-weight: bold">carbs were rebuilt</span> in the restoration ~15,000 miles ago. His temporary fix was to increase my idle speed; I have <span style="font-weight: bold">not rebuilt the carbs yet</span>. I guess I will if y'all think it is most likely the real problem.

??? I'm confused, were they rebuilt or not? I wouldn't think the bushings would wear out in 15K.

One thing you can do is warm up the engine and spray carb cleaner on the outside of the throttle shaft and note any change in RPM. I like the little straws that come with the can, they help keep overspray from going in through the normal way via the air filter.

Might want to check the sparkplugs when the car dies to see if you're running lean.

Last random thought would be the radiator shroud. Is it installed correctly?

 

[zblu]

GregW
You could use soapy water

 

[Cottontop]

Get the sleeved 160 deg T-stat that BCS in Stockton sells - it has a wider mouth so allows more coolant to flow.

Dare I suggest completely removing the thermostat to see what the baseline temperature of the cooling system really is ?

Tim

 

[GregW]

Can't say I've tried soapy water for a vacuum leak. I do for checking high pressure when I'm dubious of my oxy/acetylene tanks. Wouldn't need to worry about spraying carb cleaner on a hot exhaust manifold then. Some of that stuff is pretty darn flammable.

 

[zblu]

GregW
Its a cohesive thing, hows that geetar of yours sound?

 

[Keoke]

GregW
Its a cohesive thing, Ifin it is then don't need no soap!

 

[Stretch]

Be careful on how you do this but see if you can detect how much flow you have at idle by looking into the radiator when the thermostat is open. Let the engine warm up from cold with the cap off. You may have very low flow coming from your pump or a restricted thermostat. If you see a fair amount of turbulence at idle as well as with rpm up a bit you can dismiss a number of possibilities.