Factory service literature.

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W108
W116
FJ60

True. For that model, 0W-40, 5W-40, 5W-50 can be used at all temperatures. As a matter of fact, even 0W-30 and 5W-30 can be used at all temps. This is from the 2006 approved service products brochure.

So what do you guys think, Delvac 15w40 will be ok for the cold days in January-February, or should I change to a 5w40 grade?

15W-40 is a bit too thick in the winter where you are. I would suggest 10W-40 or even 5W-40 for Nov - March. The 5W-40 is going to be synthetic.

This will cause some controversy. On my 1997 E320 (same engine as yours), I uses 1 gallon of 15W-40 (I love these universal oil for both diesel and gasoline engines) and then about 3 quarts of synthetic 10W-30 or 5W-30. The purists will yield but I know my engine is not going to fail because I use this brew.

Thank you Loubapache for your reply. I'm leaning more towards using a 10w40 or 5w40 now. Is there a Delvac 5w40 (dino) or a Rotella 5w40?

There is a Delvac 1 5W-40 but it is synthetic.

There is also a Rotella T 5w40 but it is also synthetic.

You can buy the Rotella T 5w40 at Wal-Mart for about $16 per gallon.

Some people will argue what a synthetic really is but these are what the manufacture call them.

Too bad they are synthetics. I don't really want to use a synthetic oil, so I will have to settle with a Quaker State or Valvoline 10w40.
Thank you again.

Please provide a copy.