What could the problem be?

CyFi6 · 07-06-2008, 05:14 AM

"when piston rings are worn it allows the compression from the cylinders past the pistons down around the crank and into the oil pan. this increases the oil pressure."

This is not true at all. What you said about the dipstick is partially right, but if this is happening, i would be checking to make sure the PCV system is clean and in good working order before assuming anything else. Oil pressure increases with engine rpm, and has nothing to do with the amount of throttle you are applying. Oil pressure is higher than the amount of air pressure the crankcase could hold without blowing something out, so pressure in the crankcase does not change oil pressure at all.

What you need to do is a dry and wet compression test. Doing a regular compression check, and then add a little bit of oil into the cylinder and do another compression check. The oil between the piston rings and cylinder walls create a temporary seal, and if your wet test numbers jump more than about 20psi, its a pretty good indication that your piston rings are not sealing properly.

This doesnt seem to be the biggest concern though. If you are losing that much oil you are either burning it or leaking it. When you say the smoke is the "usual grey", what does that mean? No car should be smokeing. Does it look pure white? or does it have a slight tint of blue to it?

The fact that you are overheating is something you need to look into. You say the overflow tank has coolant in it to the full line. Does is your radiator full? Does the overflow tank spit out coolant ever?

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07-06-2008, 05:14 AM	#8
CyFi6 3" Exhaust Join Date: Oct 2007 Location: SLO Posts: 234	"when piston rings are worn it allows the compression from the cylinders past the pistons down around the crank and into the oil pan. this increases the oil pressure." This is not true at all. What you said about the dipstick is partially right, but if this is happening, i would be checking to make sure the PCV system is clean and in good working order before assuming anything else. Oil pressure increases with engine rpm, and has nothing to do with the amount of throttle you are applying. Oil pressure is higher than the amount of air pressure the crankcase could hold without blowing something out, so pressure in the crankcase does not change oil pressure at all. What you need to do is a dry and wet compression test. Doing a regular compression check, and then add a little bit of oil into the cylinder and do another compression check. The oil between the piston rings and cylinder walls create a temporary seal, and if your wet test numbers jump more than about 20psi, its a pretty good indication that your piston rings are not sealing properly. This doesnt seem to be the biggest concern though. If you are losing that much oil you are either burning it or leaking it. When you say the smoke is the "usual grey", what does that mean? No car should be smokeing. Does it look pure white? or does it have a slight tint of blue to it? The fact that you are overheating is something you need to look into. You say the overflow tank has coolant in it to the full line. Does is your radiator full? Does the overflow tank spit out coolant ever?