Thanks for that info! I am going to be changing the oil this weekend. I have stalled, because the oil has stayed so clean. I am 4000 miles on the oil now, but it still looks clean, but its 1/2 quart low now, so I guess I will go ahead and change it.

Only using 1/2 quart in 4000 miles is pretty good for a M103 isnt it?

I have a MB filter... I looked and the filter is mounted upside down... I bet this creates a huge mess on the engine doesnt it? Is there a trick to cut down on the mess?

I guess I will either use the Rotella 15w-40 or the Delo? whatever it was called. lol.

Probably go ahead and change out the green coolant as well.

Thanks again.

For the filter, I would unscrew it about a 1/2 turn to a turn, and let the filter drain while the oil pan was draining, then swap it out just before tightening everything up and adding the oil. Usually prevented a big mess, although you'll still drip a little.

1/2 quart in 4,000 miles is pretty good, especially if you are also leaking a little (and most seem to).

Thanks for all of the replies! Delo 15w-40 it is! Going out now (yeah, in the dark) to change it. lol.

Now if I can find a HUGE drain pan.

Got it changed, but strange, because I checked the oil before I changed it and it was slightly above the min line. However only about 5 quarts drained out, but I was able to get 8 quarts back in it. I checked it and its full on the stick. I asked my dad and he asked me if I was sure it didnt have a double sump? Two drain plugs? It dont does it? No one told me it did. Geez... hope I didnt overfill. I am now reading some threads where it says dont fill it to the max, but I had not yet started the engine, so I guess the filter will take some of this?

Hopefully I didnt screw anything up.

I just bought a 1991 300SE with 86K miles and full records, including window sticker. A real creampuff. The car is coming up on its first oil change since purchase. On this forum, I have read that starting at year model 1990, the M103 engines changed metallurgy of the cams and/or followers so from 1990 on up, the M103's don't need zinc additive. Can anyone confirm whether this is true or not? The PO in Texas used Castrol 20W-50 religiously every 3K miles. I will continue with the Castrol if someone can confirm these newer M103's don't need the zinc, otherwise I'll switch to Delvac like I run in all my diesels. Thanks.

__________________
1972 280SE 4.5
1984 300SD, 250K
1991 300SE, 89K
1992 300D (330K miles when KIA'd by mother-in-law 8/10/09 - still sitting in my barn)
1994 E320, 109K
1995 E420, 60K
Proud Member of the Mercedes Benz Club of America - Idaho Chapter

I've been using Castrol GTX High Mileage in my M103. Would Delvac, Delo or Rotella be a better choice? BTW, I use German filters only.

'88 300E, 70K miles.

In my 1987 M103 I use 15-40 dual rated for gas or diesel. For me the secret is in the ratings. I want CI-4 /SL or SL/CI-4. I do not want CJ-4/SM. You will find oil recipes change but they call the oil the same name as with the old recipe.
Every one has an opinion on oil and this is just mine after many hours spent reading . The latest oils are excellent oils for roller cam engines. Not sure if this is true for cam in my engine. I use a Mann filter.