1995 Chevrolet Cavalier Q&A
1995 Chevrolet Cavalier Question: Air in cooling system - head gasket leak?
My cooling system constantly pushes out whatever coolant I put into it. If I don't watch it, it overheats. The coolant is being pushed out by air, but no matter how many times I fill it and bleed it, there is still air getting into the system, and not much coolant getting out. Is this definitely a head gasket leak or could it be something else? It seems like the "air" mostly gets into the system with the engine running. It definitely gets some air introduced while it is warming up (but not after it has warmed up?), and there is a sudden surge of pressure when I shut down the engine, which is worse after it has warmed up. I drove it 800 miles recently with no problems, but driving half an hour to work every day causes it to push out all the coolant and/or overheat. - Theodore
Is there any apparent leak that you can see? Do you see white smoke from the exhaust? Check your oil dipstick for oil and coolant intermix. It will look like a mayonnaise that has turned. Does the coolant smell like exhaust or gasoline? If the car has overheated, there is a good chance the head gasket has blown but it should be verified. - Andy Y
Could this be your water pump? It is a common problem in 2.4L engines and causes collant loss and overheating? - waystowork
Sounds like this could be a blown head gasket or cracked head. The best test, short of the chemical "Blok Check" is start it up cold. Run just above idel for one or two minutes. Then shut the motor off. Carefully remove cap: If there is pressure, it came from combustion, not the engine heating up. If there is pressure, it could have only come from combustion gasses buidling up. DO NOT DO THIS ON A WARM OR HOT ENGINE - SERIOUS RISK OF INJURY SHOULD YOU DISREGARD THIS!! - Desertradiatorguy
Make sure that your thermometer is in the right way up. My cavalier did this as well, I could drive it and it would be fine but as soon as I turned the engine off all of the coolant came gushing out. I found out it was because the thermometer was upside down and an easy fix. - eia
I had a 1990 z24 Cavalier (which the overflow also acted as the filler...) I would pour water in and it was fine for a little bit, then it would push all the water out the overflow... when the car was running and thermostat open, it would "perk" out of the jug... I thought it was a head gasket, but I replaced the water pump and it fixed the problem. My water pump for that car only cost $32 for a lifetime (which was a smart choice because it went out again 2 years later). That has been my experience. Check for steam/white smoke coming from the exhaust, and check your oil to see if it's level has raised or it is white (meaning water is being pushed into the oil). Also check your hoses and thermostat. All are relatively inexpensive fixes (excluding the head gasket). Always start with the cheapest fixes first when the problem part isn't obvious - ChrsGuit