Originally Posted by Patman
In the case of my Corvette I decided to go the route of a thick 30. Given the choice between M1 ESP Formula 5w30 and ESP Formula 0w40, I feel that 5w30 is the better oil. It actually has a higher HTHS than the 40, a better flashpoint, and lower sulfated ash.
In the case of my wife's BMW I decided to go with the thin 40, as I feel Castrol 0w40 is one of the best choices that is readily available and has the BMW LL01 certification. The price on Castrol 0w40 in the 5L jugs up here is hard to beat too.
Hey Patman,
Correct me if I am wrong, but I believe the old Mobil 1 ESP FORMULA 5W30 has been fazed out - at least in the US, it has. Replaced by Mobil 1 ESP 5W30 (which on paper, has been "watered down" to a HTHS of 3.5 and flashpoint of 239C. Ash % is 0.8). The old formula 5W30 was 3.58 HTHS with a flashpoint of 254C. Ash% was 0.6
Since the Mobil 1 ESP Formula 0W40 now has the greater HTHS (3.54) and same level ash % as the ESP 5W30 (0.8), you may want to reconsider.