I have a 95 z28. First off I have replaced the computer cause i was told that was bad, it wasnt it was the distributor. replaced that then let car sit for a couple weeks. I dont think I got all of the air out of the system, and I let my auto body man take it to the paint shop to have some work done on it. He called me up to tell me the car got really close to the red on him. I got the car back and it did run hotter then it did before i was able to control the temperature by turning the heater on defrost full blast and it would keep it cool enough to drive. The problem seemed to get worse so i replaced the water pump. Didn't help a bit. when i filled it back up it wouldnt cool at all. It would also build up pressure in the radiator with the cap off, antifreeze would just push back out of the radiator. I was told by many mechanics that meant the head gasket was blown or the head was cracked allowing pressure to be put in to the coolant system. I did the head gaskets and and the heads plaind and it still pushes antifreeze out with the cap off, and with the cap on it gets hot. I have also replaced the thermostat, tried using the bleeder screws everything that i can think of to try and fix it. the fans do turn run. My low coolant light is the only thing that reads on my dash.

 

Sometimes these things are a bitch to bleed air out of. If you replaced head gaskets and all that, it may still have air in it.

 

I have the front of the car still jacked up to try and get the air out. I have let it sit over night with cap off and radiator full to try and get air out. Whats the best way to bleed them?

 

with car running turn the valve with the one on the line with a flat head....till it oozes out a bit then close it... air all out..

 

Check to make sure you don't have any coolant lines connected incorrectly. Namely, the TB bypass hose and the overflow/resevoir tank hose. Both connect to the radiator below the pressure cap. The hose for the TB bypass should be on the lower fitting and the overflow tank gets the upper fitting. If that's not the culprit, perhaps your radiator is plugged?