1997 Jeep Grand Cherokee Limited. Engine Size : 5.2 L.
Question: I have a 1997 Jeep Grand Cherokee Limited 5.2L V-8, about 253K miles. Used oil analysis is showing very high nickel (24 ppm in oil used for 3270 miles). A previous test done 61k miles earlier was high but not critical (11 ppm in 2045 miles).

Both tests show very low levels of other wear metals, well in the normal range. Does anybody know what parts in this engine may be coated with or plated with nickel that might be wearing out?

Answer: I don't know what the normal levels of nickel parts per million in used oil would be. We really don't get the technical in the shop. I would have to say the nickel is coming from the engine bearings. Engine bearings are made of several metals one of which is a nickel alloy. With 253,000 miles these levels may very well be normal since high mileage engines have and continue to wear out. Would not even be able to guess if it were rod bearings, main bearings or camshaft bearings. If the engine is not making noise and you have good oil pressure then I really wouldn't worry much about it. Only way to be certain would be to remove the engine and do a total tear down.