1995 Chevy Corsica cool heat...

It is pressurized by expansion of the water when it gets hot. The hose isn't necessarily going to feel hard as it is only 15 pounds and when you squeeze it you push antifreeze into the expansion tank through the pressure release valve. Is the radiator full? Is the water getting hot? do the hoses to the heater core feel hot when the engine is warmed up?

Basic physics: Things expand when they get hot and they shrink when they get cold. A system at ambient temp should have no pressure. Throw a sealed can in the fire and it will explode from pressure build up.

Does your engine heat up at all?

A couple of things come to mind:

1) The thermostat is bad. 2) There is a lot of air in the system.

I cant tell if the radiators full because there in no cap on it. My system gets filled thru the overflow tank. Yes the hoses do get hot to the thermostat and the thermostat does open. I've ran the car to operating temp with the cap off to burp it to release any air.

Thanks

The engine does heat up. The upper radiator hose gets hot where i can only touch it for a couple of seconds before I have to pull my hand away. The radiator also gets hot. I changed the thermostat twice already and no luck =\. I burped the system to release any air but maybe there is still more air. I dont believe my system has a bleeder to release any air. You have any suggestions for releasing the air? The way I did it was run the car to operating temp with the cap off, I also squeezed the upper raditor hose to force any air out.

Thanks

The upper hose is discharge into the radiator. If it is hot then odds are the thermostat is working correctly. The heater core bypasses the thermostat. With me not knowing the history of the car...

1) Are you sure the heater hoses are not on backwards? 2) There could be air in the system - heater core especially. There should be an air bleeder near the top of the engine.

Did we ever determine whether the hoses to the heater core get hot. If everything else warms up maybe the valve that lets the water into the heater core doesn't work. Some of the older cars used a vacuum operated valve, maybe that valve isn't working.