Pull the number one injector or glow plug. Just crank the engine. If oil blows out the head gasket has probably failed at the oil passage. This is a bit of a long shot with your description but is about the only fairly cheap way you might be processing the base oil through the engine. Other than the turbo bearing seals.

I am not sure if the oil passage leak would ruin your general performance though. For that matter even the turbo seals. In both those senarios the car would just smoke a lot but still preform I would think. If that oil passage is breeched to the number one cylinder you can even get liquid oil out the exhaust pipe.

It sounds more like the car should be worked up. First a compression check and go from there. Guessing at things will probably not find this problem.

It was the fuel! Turns out the stuff the PO left in the tank was some sort of rancid oil/diesel mixture, my guess is a homemade biodiesel. I drained fifteen gallons of the nasty stuff from the tank, pulled it and cleaned it out with soap and detergent and then rinsed with acetone to dry the thing out. After cleaning the screen and replacing the fuel filters and soft lines, the thing is running like a champ- smooth idle, no smoke, and decent acceleration from a dead stop. Acceleration above 40 is pretty weak however, and it only tops out at 65/70. Injectors, perhaps?

The ironic thing is I would have found this out three weeks earlier if FedEx hadn't messed up the delivery for my diesel purge kit. I had already almost despaired about ever finding the problem, but figured since I'd already bought the kit I'd as might as well use it. As soon as the idle smoothed out I smacked myself in the head. It was the fuel all along. Just goes to show what happens when you don't keep it simple. I could have avoided a whole lot of work and stress if i had eliminated that as an issue before tearing through the whole engine compartment. Instead I got distracted by long shots and by the time the purge showed up at my door I'd put dozens of hours in checking long shots.

I want to thank everyone for their knowledgeable and patient advice. I've had this car for only six weeks now but I already know worlds more about it and how it works, and i really owe a lot to this forum for that. Oh, and sorry it took so long for me to update, but i was having way too much fun tooling around town in my newly working luxury automobile.

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1986 300SDL: 386K, 200K on Engine w/#14 Head

Great to see that you solved your problem,and even better that you came back and gave us the report so many people come here and get help then never come back.It helps us all when we learn the conclusion. Thanks Don

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Red Green "This is only temporary,Unless it works!"

97 E300D 157000 miles
87 300TD ?141k? miles