Thinking of doing my first oil change on my 1990 300SE. I'm going with Mobil 1 15w50. I'm the previous owner of a 1985 300SD, so the filter situation is a bit different.

1. Remove oil filler cap and dipstick from engine
2. Place a pan to catch the appx 6.5 qts of oil under drain plug
3. Remove drain plug (looks to be about 14mm to me)
4. While draining (I usually let it go about an hour or so)
loosen oil filter (I have a 74 mm oil filter wrench) and
let draining continue.
5. After draining, remove old filter
6. Use a bit of fresh oil on rubber filter gasket and
install new filter
7. Replace drain plug with new washer fitted
8. Fill with 6 qts of fresh oil, check for leaks and proper oil level

SUGGESTIONS AND/OR COMMENTS WELCOME AS I DON'T WANT TO SCREW UP MY FIRST OIL CHANGE!

Pics of my "new" 300SE are here on the diesel forum:

http://www.peachparts.com/shopforum/diesel-discussion/316655-i-sold-my-diesel-buy-hope-i-did-right-thing.html#post2925836