I have a 1990 300D that has no oil pressure at all. My dad was driving the car one day, and he called me to tell me that the engine shut off at highway speeds. I went out to help resucue the car, and found that it would not turn over. After a while, it started to turn over to the point it would idle on its own but with no oil pressure. I pulled the filter with it running, and no oil was being delivered, as well no oil to the cam. There are no external leaks, so I think it must be the pump, oil pressure valve, or the pump drive chain.

I am going to replace the motor with a used one that I have yet to purchase. I am not sure what caused the failure, but was interested in finding out if the oil pump can be pulled and replaced without removing the engine from the car. If it is possible, I was thinking about puting a new pump on it and seeing if the thing will come back to life. If it does not work, I would still be able to put the pump into the used engine.

I noticed the oil pan is not like that of the om617. It does have a side cover though. Is it possible to check anything from that, or am I just wasting my time?