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TR4/4A Over Heating TR4A--Some Questions

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KVH

KVH

Obi Wan
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Time for action. I'm pulling my radiator--now.

Today I ran fine until I idled outside my garage after a long drive, and in just a minute or two I actually went into the red zone, even with my auxiliary fan on. That seems extreme, even despite it being about 108 degrees today.

I've got a rebuilt engine, a very clean water jacket in the block, and a 5 vane water pump, for what that adds.

I'll report what I learn, in case it's of value, but in the interim let me ask a few questions for educational purposes:

a) When I stop the car and the water spills over in the overflow bottle, what is actually happening? Is the radiator cap allowing bypass, or is the coolant just boiling on down the plastic overflow tube and over-filling the bottle?

b) The housing of my water pump appears to have a slight white residue on it, as if coolant may have leaked there, but I can't see that any leak actually exists. Any thoughts?

c) What would be the symptoms of a bad radiator cap? When I lifted the pressure release today, after the engine had cooled for about 5 minutes, there wasn't much of a release. When I took the cap completely off, however, a little more air or pressure was released.

d) Since I run at proper temperature on the long straight-aways, does any of this sound like a bad thermostat? I'm running a 160 degree thermostat.

thx
 
The shop said it was fine three years ago, so I'd assumed it was functioning OK. Then, about a year ago I took it back and the infrared gun showed 190 degrees going in and 165 coming out, so he said it seemed fine.

But since then it's possible some Barsleak I used may have gunked it up. That's my primary concern since the type I used had a warning label about that. It said to be sure to evacuate all antifreeze, and I'm not sure I had done such a great job getting it out of the block.
 
To address your questions --

On mine coolant pushes into the overflow all the time the engine is heating up and then draws it back as it cools -- nothing dramatic happens when the engine shuts off.

I have never seen coolant leave a white residue (assuming distilled water & antifreeze is in there).

A bad radiator cap that failed to hold much pressure would not offer much symptom -- mainly it would lower the boiling point of the coolant.

A tstat stuck closed would indeed cause overheating -- I think they are designed to fail open but maybe that is not a sure thing.

I would start checking things with an infared thermometer (cheap at harbor Freight these days) looking at: accuracy of gauge, temp drop from top to bottom of rad, confirming tstat is opening at about the right temp, etc.
 
Kentvillehound said:
...the type I used had a warning label about that. It said to be sure to evacuate all antifreeze, and I'm not sure I had done such a great job getting it out of the block.
Click to expand...

That sounds more like a ceramic sealer as opposed to the traditional 'flakes & goo' Bars Leak. Have no experience with that method (remove antifreeze, run with plain H2O & sealer, drain completely, let dry) so I do not know what risks come with it.
 
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