89Camaro89MI

iTrader: (2)

I'll try to make this pithy

My 89 has a 305 that hits the redline on the heat gauge after about 20 miles. When I turn my car off, I get a gurgling noise, like a roiling boil, in my overflow tank for about 30 - 60 seconds.

My diagnosis is that I've got a headgasket that's leaking pressure from the combustion chamber into my coolant system that my pump isnt able to overcome.

I loosened my radiator cap and drove it for about 10 miles, and the temp didnt even hit 220. It isnt my thermostat, and I've got plenty of coolant.

Does this seem valid to anyone? Anyone seen this before and/or know how to test for it?

Thanks

Richwiz1

Stupid question are your fans /fan working. Is water circulating? Do you have white smoke out exhaust?

camaronewbie

1) Have you replaced the radiator cap? (that's cheapest first thing to try)
2) Why is it not the thermostat? Brand new ones are often bad - have you removed it and boiled it in a pot on the stove to verify it's opening?
3) Are the fans coming on?
4) Is the air dam in place?

Don't jump the gun and assume the worst case scenerio - head gaskets don't go bad that often. 99% of the time overheating is something else. Gurgling noises happen with any overheating issue, regardless of the cause.

86FireBird305

If the head gasses were getting into the cooling system it would take less than 20 miles for the needle to pin.

Does the heat drop when you give the car gas?
Whats the condition of the coolant and when was it last changed.

89Camaro89MI

iTrader: (2)

Okay, all the questions...

I have verified while it was running that the thermostat was opening up. I just changed the coolant about two weeks ago when my Coolant line to Heater core valve (the thing just kind of hanging out on top of the passanger side valve cover) exploded. My suspicion is the pressure buildup is what caused it (probably should have mentioned that). It broke at the line that runs from the back of the engine.

My water pump is about 2 months old, which was when I'd last changed the coolant.

I often smell coolant vapor, but it only smokes on start up and I havent been able to verify it smoking while driving. The smell could just be coming from my engine bay.

Yes, the fan works.

I havent replaced the radiator cap - mine seem fine...

Yes, the air dam is there.

I havent noticed the heat dropping when the car gets gas. 20 miles was a guestemate - it could be less, and it's done it faster than that on me. 5 miles or less. It was 20 miles on a cold Michigan morning last week.

I think that is it. Could it be the radiator cap? I'm not loosing any coolant, and I've been checking my levels.

Thanks a lot

Richwiz1

Do a compression test.