I have an 85 IROC-Z, it always ran hot >220, the fan is rigged to run non stop when the car is running and I still cannot use the AC long. Recently it overheated and now I cannot run longer than 15 minutes without overheating.
What I have done already:
- Checked the water pump, no movement, no noise and the water is moving rapidly in the radiator.
- I replaced the 190 thermostat with a 165.
- I replaced all the hoses (they were getting worn anyway).
- I replaced the antifreeze when I back flushed the system.
- I replaced the 5 groove serpentine style belt.
- There is no oil in the coolant, I verified that during the back flush with clear water, there is not water in the oil I changed it and inspected it very closely indicating the head gasket in fair condition.
Is there any chance that compression is being forced into the water jacket and no fluids are being exchanged. This would cause air pockets and the car would overheat fast. I have noticed that even with no thermostat the up radiator hose is very rigid after a short time running.
Thanks for your help. Bryan