yes, i searched, this has never been addressed before (that i could find).

ok, i need to change my oil and im going to switch to synthetic (mobil 1). up till now ive been running pennzoil 5w-40, but they dont make mobil 1 in that.

in my search i found that the two most popular Mobil 1 weights here are 15w-50 and 0w-40. the first for its better protection, the second for its easier cold startups. but i live in houston and its the summer so sub-zero startups will never be an issue.

the reason i cant decide is because unlike most diesel drivers, i usually only put about 5-10 miles per day on my car. my commute is very short and i almost never have time to let my engine warm up. however, i do occasionally take very long road trips.

my question is, which weight oil is better for short trips running in a cold engine, but still provides good protection for long trips in 95F+ weather?


please try to stay on topic for everyones sake.

thank you.

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1991 300 D 2.5 Turbo, 220k
also in the family:
1981 240 D 185k
1991 350 SD 185k
2006 S 500
2005 SLK 350