overheating problem

[Greg Hansen]

I have a 69 with original 350/300hp engine, auto, and ac. Lately it has had a mild overheating problem, I flushed the radiator, changed the thermostat, and while refilling the engine with coolant I noticed that there were tiny bubbles (they looked like soap suds) in the coolant. I suspect that I have a bad head gasket. Does anyone have any other ideas? Thank for any advice or info.

[Joe L.]

Re: overheating problem

Greg------

A head gasket leak is a possibility, but not a certainty. Have a "block test" run on the car. Any good automotive repair shop should have the equipment to perform this test and will likely do so for a nominal cost. This test is used to detect the presence of combustion gases in the coolant. If the test is positive for combustion gases, then you have a head gasket leak (or a cracked block or head). If the test is negative for combustion gases, then, happily, you know that you have to look elsewhere for your cooling problems.

[Terry R. Payton]

Re: overheating problem

Greg-I spent $$$$$$ trying to figure out my overheating problem was. What are the chances of getting to bad "new" thermostats? well, thats what it was. Think small first. Good luck TP

[Mike McKown]

Re: overheating problem

Greg:

I lost a head gasket on two different occasions. The symptoms were bubbles in the radiator, engine miss on start-up after sitting idle all night and rust/condesation on the spark plug electrode. Again after sitting overnight.

Are you sure the bubbles were not just stray air pockets venting from the flush?

You can take the thermostat housing off (good time to check it on the stove in boiling water), remove any belt that would turn the water pump and start the engine. If you observe bubbles here, you can bet you have engine compression leaking into the coolant. If you don't have bubbles, you need to look elsewhere. You don't indicate if it is a low speed/high speed problem.

Oh, if you see bubbles you can try Barr's stop leak if you are on a budget or too busy or whatever. Sometimes you can get lucky with that stuff.

Mike