I tried Pennzoil synthetic Blend 5w30 on a 3.3 chrysler v6 and it seemed to burn/ leak faster than the Pennzoil yellow bottle. Also on one occasion when started after sitting for 4 days it sounded like a rod knock for about 3 seconds. This also happened on a 2002 3.0 mercury mariner one of my engine rebuilders owns.. I think i am going back to regular dino both engines have over 150,000 miles on them but usually run very good. the 3.3 had a napa gold and the ford 3.0 had a motorcraft both had around 1500-1700 miles on the oil. Anyone else have this problem?