Timo Schroeder

Gents! I got a little in doubt about which engine oil I should use, for my M278. I get conflicting information when I research the topic. Mercedes prescribes 229.51 - fine enough, but I can both find it with a viscosity of 0-40 or 5-40. The car has always been driven on the oil recommended by the Mercedes workshop, from Mobil 1 the first 9 services and the last 6 services on Castrol Sport. I just bought the 20 Liter Castrol Edge Titanium 5-40 that complies with the Mercedes 229.51. But have now come into doubt I might should have bought 0-40 instead. Both oils comply with Mercedes 229.51 - so ...... I live in the south of Europe, Hungary and we have mild winters here.

vettebk

Are you having trouble sourcing 0W-40 Mobile 1 ?

Timo Schroeder

No not particularly. I was just confused about the difference in the information. But as long I go for a 229.51 it have to be good. But anyway thanks for your reply.

Senecat

5w-40 is fine. The graph in your Owner's Manual tells you everything you need to know. I live in Tampa, FL, so I can get away with heavier stuff. Freezing temps and lower, run thinner for startup. That's all those numbers mean. None of it really even matters as much as simply making sure the oil and filter are changed regularly.

Arrie

5W40 is very fine for you. Even 10W40 should work unless you get very cold days during winter.

I don’t know how warm days you get summer time but it probably gets to 30C and above at times so I would hang on that upper value 40.