hold on a sec!
the 603 came in several varieties, the 603.960 is the 2.995 liter engine use in the used in the '87 300D, '86 and '87 300TD and the SDL turbos.
It's not a "bad" engine, if you get the trap oxidizer off of it and the owners replace the radiator when its plugged and use the right coolant and R&R the vacuum pump, all those models are prone to problems related to those things.

The '90 and '91 350SDL and '91 350SD both use the 603.970 engine. That is however a sad story and a blemish to MB's engineering skills. What with the rod problems its another thing altogether so please don't classify everything as a 603 problem
the '94 (W140 chassis) used the 603.971
I don't have any direct knowledge of what changes were made to the engine but presume they modified it, but its still suspect

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!