I purchased a 1991 350SD from a fellow that stated he was driving it down the highway, and without warning, immediate plumes of smoke came from the car. He pulled over, and shut it off, and was able to restart it, but very rough running. I started it up yesterday to load it onto a trailer, and the smoke was immense. WAY more than I have experienced with any rod bending OM603. My plan is to swap a 3.0L into it. I didn't this earlier this year with a 350SDL, and it's worked out great with some extra work and swapping components over. But, I started thinking today. The rod bending symptoms tend to slowly manifest themselves over time. He said it wasn't smoking (not more than usual) and he wasn't having to add oil often before this suddenly happened. I had a couple other ideas. Let me know what you think about these possibilities...

Catastrophic Injector Failure - This could possibly cause fuel to be just dumped into the chamber, and produce the smoke I am seeing, and definitely cause the rough running condition.

Bad Modulator Valve - Pulling transmission fluid up and burning it.

Bad turbo seal - Not really sure here as they aren't liquid cooled, but not sure if this could be tied to a common failure of a turbo related component.

But anyway, the second the car starts, it plumes so much smoke, it's blinding. And it runs extremely rough.

I was first thinking of removing the injectors, and taking a compression test, and go from there.

I dont mind using the 3.0L OM603 I have and swapping it in, but if repairing this engine takes less time, I'd rather go that route, and put the 3.0L aside for a rainy day.

Any suggestions? Am I on the right track so far?

Also, no knocking sounds or anything like that.

And he is running Bio-Diesel in it, so I'm not sure if the injector is bad, what the fuel would smell like. It smells a bit like sulfur.

I turned it over without glowing it, and it sounds like one cylinder is missing. Would fuel washing the oil off the cylinder walls cause an irregular missing when turning it over?

Thanks!!

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1987 300SDL #1, 1987 300SDL #2, 1980 240D, 1982 300SD, 1994 S350, 1990 350SDL, 1991 350SD, 1985 300D, 2005 E320CDI

Gone, but not forgotten: 1981 300SD, 1982 300SD, 1987 300SDL, 1983 300TD, 1980 300CD, 1981 300SD #2, 1987 300D, 1987 300TDT, 1980 300D