[JFP in PA]

Originally Posted by flintworks

2 out of the 3 dealerships I've worked at used Mobil 1 0w-40. We're talking about thousands of oil changes a year just from one dealership. If there was a problem with that oil Porsche would remove it from the approved oil list and we would have seen more internal engine problems. The third dealership used Valvoline 0w-40 simply because it was cheaper than Mobil 1 and I believe Porsche approved it for use this year. In my opinion it's more important to keep the oil clean than debate which synthetic has the greatest protection.

We probably average 12-15 oil changes a day, six days a week, and have done so for more years than I’d care to admit. Along the way, we have regularly taken samples of oil for analysis; recording literally hundreds of results for several brands and many grades of oil; both synthetic and “dino”.

What did we learn? Mobil 1 used to be a great oil; but it no longer is. Amongst the poorest performing grades under even minor exposure to heat or shear: 0W-40. Mobil’s 15W-50 continued to be a good performer, but that also changed about 3-4 years back, about the same time it lost all of ACEA ratings it once held. Now it is a shadow of what it once was, particularly in its performance in used oil analysis.

Considering that the degradation of the Mobil 1 line did not happen over night, and has been the “topic of discussion de jour” on multiple web sites, I find it hard to believe that anyone remotely knowledgeable on the subject continues to believe it is a first rate product. Based upon what we have seen, we made a conscious decision to no longer use it in customer’s cars. Based upon our on-going data collection, that has proven to have been a wise choice……………..