PeachParts Mercedes-Benz Forum - View Single Post - 87 300D totalled in accident thinking about S class

Jeremy5848 · #14 01-31-2010, 11:32 PM

The 90-ish W140 diesels had an OM603.970 engine that was bored out to 3500cc to make more power/torque to push the bigger chassis. Unfortunately, they didn't sufficiently strengthen the con rods and this engine is now known as "the rod bender." The rod bending is slight, can't be detected by driving, can happen at any time/mileage, and causes the pistons to carve the cylinders into an oval shape. The first clue is that oil use has gone through the roof.

Mercedes developed a stronger rod and even replaced some at no cost in cases where it was to their advantage (good customer, low miles, etc.) PR-wise. The chances of getting that to happen now are not good. Some forum members have these cars and are well pleased with them. If the rods have not yet bent, the engine runs very well and the car is otherwise excellent or so I have heard. When the rods do bend, you throw away the car or look for a replacement engine, such as the 603.960 engine in your wrecked '87.

This is not meant to scare you away from the 350SDL but you do need to look at what might happen. I would not pay very much for one, given the risks, unless the engine had been rebuilt or replaced. If you are simply looking for a larger version of your '87 300D, consider an '86 300SDL. Same engine in a foot-longer body.

Jeremy