Ran Pennzoil Platinum 5w20 for 6k oci in my Jeep Wrangler. (Total of 29k miles, and I go by the OLM) Changed it today to Mobil 1 5w20. I've been runing Ford Motorcraft oil filters on the Jeep as recommended by Jeepers on JK-forum.com. Jeep JK owners had been having trouble with Mobil 1 filter anti-drainback valve and getting bad noise on starts. I experienced this, as well the one time I ran that filter. The Motorcraft filter works well, and they are cheap. I bounce back and forth between Mobil 1 and PP, primarily going with Mobil 1 for winter. I guess I believe it flows better cold, but I don't really know if that is the case.
This engine sounds the same with either oil, so other than the aforementioned perception, I have no other ideas about which is better. I've had great luck with Mobil 1 on other engines for years, and I see so many good used oil analysis on PP, so that's why the waffling. (Plus, I occasionally score PP at a low price.)
I've got Mobil 1 5w30 in my Solstice now, as well, with a Supertech cartridge filter. I go by the OLM or 1 year, whichever comes first. This time, the year came first. I've got 24k on this car, but didn't put many miles on it last year. It went about 5k on Pennzoil Platinum 5w30 last time, and the OLM was at 48%. Same deal in my head between the two brands of oil. Again, I hear know audible difference between the two oils. I had a used oil analysis done on PP a couple years ago and it was excellent. I also had trouble with a PurOne oil filter. The media began to deteriorate at about 4 or 5k on the oil. Supertechs have done very well. I ran one to around 8k miles and it looked great.
