Running hot 1996 cavalier

Please try a simple test for me. no.1: remove the radiator cap off the radiator. no.2: if you could see the see the radiator opening from within you car much better, then try to crank your car to an idle. if coolant blows out of the mouth of the radiator like an erupting volacano, then take note of this. no.3: while the engine is running at idle try to look at the coolant through the mouth of the radiator, if you see bubbles like washing your hands with soap and the suds trailing to a drain, then take note of this.

the reason why i'm telling you all of this is that, the coolant should flow like a clear stream. you don't have to worry about purging the system of air because, the water pump is already situated a few inches below the highest water capacity of the radiator. it means that if you drained your system and refiled the radiator to the brim, just start your engine and add a few more coolant to fill it up because the running engine simply purges the waterpump of air.

now, if you tried no.2, and you did see and somewhat like an errupting volcano, that means your engine is in serious trouble, so is no.3. however, a tolerable bubble flow is still possible but your valve clearances should be tuned if this happens. excessive bubbles accompanied by blow out of coolant means your combustion gases are seeping through the head gasket due to a damaged head gasket, warped cyclinder head, cracked cylinder head, or even a cracked cyclinder liner(or bore where the piston glides up and down). think back! did you ever experienced overheating you car to a point where it stalled completely? then, you need a thourough engine checkup.

Try bypassing the heater core. i've found that chevy's are prone to this. did you replace the radiator or do you need to. pressure test it. but this is common among chevy's. bypass heater core .