Went to WalMart to buy the usual MOBIL ONE 15-50 wt. five quart jug for $19.88 but not available any longer. Instead, there was a 5 Qt. jug of M-1 labeled for diesels and gas engines 5-40 wt. for the same price.

Looking down the shelf I noticed MOBIL ONE 15-50 wt. was available but assume was renamed to SuperSyn, or something like that, and was $23.88 for 5 qts.

Hmmmmm, I thought and wondered about 5 weight as being lower than I would like having heard that wide spread oil weight such as 5-40 was not good!

Looked at another shelf and it had ROTELLA T synthetic featuring ADVANCED SOOT CONTROL, but also was 5-40.......but hay, the price was $13 and change but was a 4 quart jug, still cheaper than Mobil One, and I didn't have to buy 10 quarts (2 jugs) of M-1 spending over $40, but instead I bought 8 qts. of Rotella syn for $28 and change.

Question: Any reason why I shouldn't run ROTELLA T synthetic 5-40 instead of Mobil One's 5-40 diesel specific version of the same thing, or was I better off with the M-1 15-50???????????? .........BB