Hello to everyone, I am a new member looking for some answers for why my 2004 WJ V8 is burning oil (like crazy). I bought the Jeep last year and soon after I realized it was burning or leaking oil. It is a 2004 Jeep Grand Cherokee 4.7L V8 with 152,000 miles. Its burning about 2 quarts a week. Theres no blue or white smoke from the exhaust but it does smell like burning oil.

A mechanic recently told me that the problem is a leak at the main seal. Another told me it's the piston rings. I'm just trying to figure out if the problem is repairable or if its worth the cost to replace the motor. Can anyone help me diagnose the issue? Thanks in advance

 

You have helped me numerous times as we own a Fiat freemont, jeep wranglers and a Cherokee. If you ever service a Smart car 450 I’d be very interested! Merry Christmas to you, the team and your families, and look forward to more videos next year.
Kodi nox

 

Two things you can do to find out about the rings. Do a compression test and a cylinder leakdown test. The compression test will nail down which cylinders are leaking and the leakdown test will tell you if it's the rings or valves leaking.

If the rings are leaking compression into the crankcase, the blowby can be coming into the engine thru the crankcase vent and being burnt in the cylinders. This can damage the converters by building carbon in them.

If you plan on keeping the jeep, you might want to think about replacing the engine with a good used one, if you can find one. Rebuilding the one you've got can get expensive quickly and buying a rebuilt is even more expensive considering labor costs. I could be wrong, but I'm thinking at least 25 manhours to remove and replace an engine in any vehicle. That's from running to running. Not just the physical part of it.

These are just my opinions and should be researched further. The 4.7 is a good engine if taken care of. If not, they can go sour fast.

 

If the rear main seal is leaking two quarts a week, you will see plenty of oil under the vehicle. Get under there and look.

You will probably also see plenty of oil staining where you park.

 

Something Dave said regarding compression brought back the memory of a similar problem. We had a Dodge pickup In the Fire Department about the same year of your WJ, and it consumed oil like crazy but with no obvious symptoms, well, our fleet mechanic found there was a hole in the top of a piston. Perhaps this could be a possible problem with your WJ, the engine in our pickup had to be replaced.