Hi All,

I have a 92' 300e (2.6L engine) with 148k miles and it is burning approximately 1 quart of oil every 500 - 600 miles. The previous owner used regular 5W - 30 oil and I am now using 20W - 50 to reduce the burning.

I changed the valve stem seals and the engine runs great but it burns excessive oil. The compression test was consistent across all cylinders (165) and the leak down test demonstrated consistent (10 - 12%) across the pistons. I do not see smoke coming out of the exhaust pipe. The spark plugs do have oil residue after a few thousand miles. I think it is also leaking a bit from the head gasket. The increased oil consumption also seemed to occur rather sudden.

Based on your experiences, do you believe it needs a head rebuild (valves, etc) or do you believe it is the piston rings? Is their a type of oil or additive I can add to reduce the oil consumption? Any other tests?

I truly appreciate any guidance since I don't want to spend the money to rebuild the head when the piston rings are bad. Thanks!

Best Regards,
Louis