What is the differance between 603s ?
 

Hi what is the differance between 1987 300sd and 1993 300sd than there is the S350 3 differnt motors or what ?I get 3 differnt storys. thanks J:confused:

Yes, three different engines.

1986-1987 3.0L OM603.96x, known for it's risk of cracking the head.
1990-1995 3.5L OM603.97x, known for randomly bending connecting rods and extreme oil consumption afterwards.
1990-1995 3.5L OM603.97x, rebuilt/replacement by Mercedes, far less likely to have rod issues.

I know, I love the 617 also ! but what cars had the better 603's ?

IMHO, anything with the 3.0 liter version, or anything before 1990, IIRC. I personally would not trust even the factory rebuilt 3.5 version.

Tom W

IMHO any 603 with a #22 head. Others will disagree, but there are plenty of cracked ones out there. Having said that, it is still cheaper to do the top end than to replace the whole engine. So the best ones would be found in the 1987 300D/TD and the 1986-87 SDL. Those are the only years for US imports. The OM603 was used in the rest of the world until 1989, AFAIK.