a friend of mine jus swapped in a j-spec 3sgte into his 93 toyota mr2. it was running perfect for a month, but then he noticed he was leaking a little oil. first he thought it was his oil seals, but 2 mechanics he went to put there money on the head gasket. when he originally got the motor he compression tested it and the compression was near perfect... would a compression due any good to check and see if the head gasket is going out on him? we also noticed that when we pulled out the oil dipstick from the motor the oil jus fell rite off the dipstick, it was real thin so im hoping the coolant didnt mix with the motor oil....... any suggestions for my friend in need?

 

A compression test will tell you if you have an oil leakage from your oil lines to your cylinder. It's possible that your compression test will look great but your head gasket is still leaking. Go ahead and do a compression test, as it wouldn't hurt. If antifreeze is getting into the oil, you can try checking under the radiator cap. Maybe there'll be oil in your coolant, too. That'll be easier to tell.

 

yea i know, the thing is the coolant that is in his resovoir is the same color as his motor oil, so its hard to tell, i think tomm we are going to pik up some green prestone antifreeze and put it in sop it will be easier to tell the difference

 

If the head gasket is blown, a compression test will confirm this but not every time. The purpose of the head gasket is to seal the cylinders and the cylinder head. If the head gasket is blown, it will not seal the cylinder and the cylinder head. This will result in loss of compression. If the head gasket is blown, you can get oil burning and coolant/oil mixing. Compression tests are easy, especially on a 4 cylinder engine (unless its a boxer) and you can rent a compression tester from autozone for free. Do a dry compression test and do a wet compression test. Wet is when you put a little oil in the cylinder. If your piston rings are not good, the oil will seal up the space between the ring and the cylinder wall and you will get better results. A wet compression test won't really tell you anything about the cylinder head and head gasket, but its not a bad idea if you are doing a compression test anyway. Basically, it can't hurt to do a compression test. If the comp test comes out bad, you know you will have to take the cylinder head out to find out what is going on.