My 99 Durango with the 5.9 is chugging oil like crazy. I took a trip on the highway that was roughly 150 miles and it used 3 quarts of oil. Same on the trip home. 6 quarts, 300 miles. No indications of it leaking externally. It runs just as it always did, no missing or anything like that. It dont seem to be smoking out the exhaust, hard to tell at 70 MPH. Any ideas?

I noticed a TSB somewhere on this, I believe it said spark knock and engine oil consumption. It invloves the intake manifold plenum pan gasket. The oil leak would be internal, you wouldn't find any on the ground.

I can't say if that is your problem, just a thought.

09-005-00

plenum gasket. A very bad one at that.