Mechanics

SATURN SL2 COMPRESSION PROBLEM

1995 Saturn SL2 • 176,358 miles

I have a 95 saturn SL2. Approx. 176*** miles. Smoking real bad, using oil, running really rough. Take out the spark plugs and the number one cylinder has oil sitting in it, the other three cylinders are good. So I pressure test all the cylinder. All are readying 130-160 psi except number one again, it only holds about 15-30psi. I was wondering does this mean the rings are bad, or could it be just the valves burnt causing it not to hold compression? Pretty sure the head gasket is at least shot.
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Iowan86
April 1, 2013.



Min compression is 175 psi on that engine so all the cylinders are low. But most likely valves causing your 15-30psi compression. But for the oil consumption probably a combo of worn valve stem seals oil rings and possibly worn uneven cylinder walls common on those cars.

Saturntech9
Apr 1, 2013.
The cylinder pressure on the other ones was just rough estimates, I was just wanting to make sure they was holding pressure. Besides doing a complete teardown, is there anyway to check and see if the rings are any good in that number one cylinder?

Tiny
Iowan86
Apr 1, 2013.
Chances are the rings are not the problem. However, if you want to check for ring problems you need to do a wet compression test. First, check the cylinder dry and get a reading. Then put a small amount of oil in the cylinder and check to see if there is an increase of compression. If there is, the rings are bad. If there is no change, the valves are the problem. My guess is you have a stuck, bent, or burnt valve.

Most likely a burnt valve you can do a cylinder leak down test that will tell you where and if its intake exhaust valves or rings. But with compression that low its a most likely a valve. But you still have the really bad oil consumption problem. So I would say your engine is gone. If it was my car I wouldn't fix that engine.

Saturntech9
Apr 1, 2013.
Well there was oil just setting in the cylinder. I am assuming this is most likely from a bad head gasket? So without the oil just pouring into the cylinder it may not use that much oil?

Tiny
Iowan86
Apr 1, 2013.
The oil your talking about is it on the outside of the plug?

Saturntech9
Apr 1, 2013.
No it was inside the cylinder setting on top the piston. The valve cover looked like it had a good seal.

Tiny
Iowan86
Apr 1, 2013.
You could have valve stem seal issues oil ring/cylinder wall wear issues.A head gasket isn't going to make it use oil like that.I know these cars well.

Saturntech9
Apr 2, 2013.
Ok thank you, going to just put it back together after putting a new valve cover gasket on it and cleaning it up some, and drive it till it dies!

Tiny
Iowan86
Apr 4, 2013.
Keep oil in it and it will run for a while like that.

Saturntech9
Apr 5, 2013.