I have a 79 corvette, my temp gauge is displaying that the temperature is past the redline, i just replaced the coolant for the radiator, there is no steam coming from the car. I did just change the oil recently. My car has overheated in the past and I replaced the thermostat and that seemed to fix the problem but recently my car did overheat, I checked to see if the heads were fine and they were. why is my temperature reading so high?

 

Man you should have seen my earlier posts. I also have a 79, and after spending lots of time and money on possible solutions external to the engine, it turns out that I had a blown head gasket. There was no oil/water contamination evident. Running the engine at excessive temps. did cause a lot of internal damage to the valve train, as the valves were binding in their guides and got hammered badly, as well as the cam and lifters. I hope that you get off with less damage than I did. Good luck with your troubleshooting!

 

Are You Low On Coolant?? Or Could Be Thermostat Again

 

What did you do to "check the heads" ?

 

When is it overheating? all the time or just stop and go type traffic or also open highway driving? Are you actually puking coolant or is it just the gauge reading that is telling you it's overheating.

FIRST thing I'd do if it's not puking coolant and no steam is to get an IR temp gun and shoot the upper radiator hose to see what temp it really is and compare it to the guage to make sure you are seeing a correct reading. I fought an "overheating" problem for weeks on my '65 before I realized I never had one at all, it was just my temp sender had gone bad and was reading 40* too high!!

If you really are overheating:

check your t-stat again
check your fan clutch
check your hoses and make sure they are good and not collapsing inside causing the coolant to not flow properly.

are you running the stock fanblade or an aftermarket flexfan - they are not nearly as effective as the stock fans.

do you have all the correct seals around your radiator and core support? these are imperative to have installed to make sure all the air flows thru the radiator rather than around it.

do you still have the air dam under the nose of the car? This is very important to bring air up and into the radiator area for cooling. Without it the cars don't get enough airflow.

Waterpump working properly?

 

thanks for the suggestions i will try them. I checked the heads by seeing if there was water in my oil, thinking about taking it to a mechanic to make sure they are fine.