I have a 97 cavalier 2.2,and recently the car wouldnt get warm and the heater wasn't working worth junk ethier.....So all being signs of a thermostat I went a installed a new one and still the same problem....So thought maybe an faulty thermostat so took it back and got another one and now still the same problem..... Well sometimes it seems to heat up but i have to let it sit for awhile and them it ends up dropping again all the way back to the first line after the C.... So i was wondering if some one could help!?!?

Umm did you get all the air bleed out leaving off the resevoir cap to alloy air to escape while the car is running helps being it sounds like air pockets maybe.Unless ur water pump is going or ur heater core is leaking or blocked that is what comes to mind.U would use some cardboard placed in front of the radiator let the car idle for 15-20 at idle with heat on high setting and resev cap off and see if any change.As long as there is not a wet spot on the carpet on the passenger side from the heater core from leaking it may be the pump not circulating properly and check to see if the upper and lower hoses get HOT afer the time above if they are both hot that means the pump should be working.A simple check for the pump is to squeeze the upper hose car hot (warm) and release u should feel pressure kick back which is the pump working.The cardboard just speeds up the process of heating up the engine.That is what comes to mind and may others add or correct me if need be.

okay so i'll try this later on today and let you know if it works thanks