2000 CAVALIER 2.2 OHV so let me confirm #1 180psi #2 140 #3 155 #4 180psi on dry comp test. on wet test numbers were about 200psi across the board? Originally the car overheated. i changed thermo, rad, water pump, and belt. still overheated. i was told i may not have bled out all the air. not sure if i did it right. how is that done? i smelled exhaust fumes in over flow tank. I ran car cold for 2 minutes, shut it off and pulled off rad cap and there was alot of pressure. i ran car with no thermo and it did not even come up to temp, put it back in and still overheated. fan works, heat works, no sweet smell in exhaust, no oil in coolant, no coolant in oil. i do hear a hissing coming from the overflow hose in coolant res. i just noticed a freeze out plug is leaking coolant, and the first exhaust manifold gasket is bad i see smoke coming out. Is it possible the head gasket is blown? is that why #2 and #3 cylinders psi is lower than #1 and #4. Also with the wet test are those numbers ok. I am at a loss. my father keeps asking why i am wasting my time, energy and money. and the truth is i love my little car, and when i start something i must finish it. i refuse to pay someone to anything if i can do it myself. i am a top notch carpenter, not an auto mech, but i am mechanically inclined and love to read. i learned everything i know by reading. I just need to know for sure if it is the head gasket... Last night i pulled the exhaust manifold off cause i broke a bolt trying to put a new gasket. Should i fix the freeze plug and exhaust gasket, put it all back together, or go a little further and do the gasket if that is what it is.......THANK YOU SO MUCH JOE
Could be head gasket causing the lower numbers. Hard to check since you have a freeze plug leaking. Normally would say to do a pressure test on cooling system with spark plugs out. If pressure starts to drop and coolant shows up in spark plug holes then it's a blown head gasket. Might try using a temp rubber freeze plug to seal that leak then do the pressure test on cooling system. Your compression numbers look with in range but don't like it if any are more than 5 psi different than the others and you have two that way.
To test the cooling system for a blown head gasket. Pressurize the cooling system (cold) with a cooling system pressure tester. Then start the engine. If the needle on the pressure tester gauge bounces the head gasket is blown. Pull the oil dipstick. Is there white milky "goop" on the dipstick? If so, that's another good indicator of a blown head gasket. The fact that the compression readings improved so much with a wet compression test tells me the piston rings are worn. It might be time and, in the long run, more cost effective for an engine rebuild or engine replacement. HTH. -Jim
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