2000Z28AUG

Alright guys . . .
I'm completely stumped! I just spent 8 1/2 hours in my shop and cannot find a SURE solution to my problem. I think i MAY have it narrowed down though.

Whats happening:

Car starts and runs fine. Thermostat proceeds to hit 220 and fans kick on. Temperature still rises all the way to 250 degrees.

What I have done to troubleshoot:

Replaced the radiator (waste of time and money) :-( . Changed out radiator caps and checked all hoses. THERE ARE NO LEAKS on/around the vehicle. I noticed though checking the top hose near the radiator cap that the car cooling system is drawing air in.

What I have drawn to a possible conclusion:

Thermostat stuck and drove the temperature to an extreme point and possibly blew a head gasket giving me a eradic high temperature then falling to 210-220 degrees. I dont think it could be a Water Pump bc. the water pump would draw high temps like this.


ANY help would be GREATLY APPRECIATED!

crainholio

iTrader: (2)

AutoZone rents a cooling system pressure test kit, go get it. The adapter goes on in place of your radiator cap, you pump it up to pressurize the cooling system and then watch the gauge. It's very easy to use and gives very good results.

I usually pressurize to 16 psi, and expect it to hold 16psi for at least 10 minutes or however long it takes me to finish my beer. In reality, a properly sealed system will hold 16psi overnight and then some.

If you warped a head and blew a head gasket, you'll lose pressure the instant you stop pumping. With a mechanic's stethoscope, you can probe the spark plug holes and find the one leaking air/coolant...you'll hear a hiss in most cases.

2000Z28AUG

thanks man... I'll try that monday. I'm thinking of getting the gaskets ordered anyway. $25 dollars in a gasket I'll probably eventually use is ok anyway. Especially if I look at doing a 440 ci build. I'll need the gasket.

crainholio

iTrader: (2)

Head gaskets? You'll need different ones depending on your cylinder bore diameter, so basic LS1 pieces will not be useful on a 440ci with larger bores.

I'd hold off buying them until you diagnose the problem and decide on next steps.

Rudolph

iTrader: (1)

I have seen problems like yours, and always:

-Thermostat

-Water pump

On road racing you really test your cooling system, and if is not rad's capacity, the problem is usually on the previous mentioned things.

BTW, you can test the thermostat by removing it and put it on water boiling Then you will se some action!! If you do not see a thing, then... you have a problem dude.