My noise was there at idle, load, and most every other situation, but it would slightly change at coast. You could tell that it got louder when you got back into the fuel after coasting.

I bought the car making this noise so I can not personally attest to the oil consumption but I know the fellow I bought it from well and he swore that he never had to add oil between changes to it.

My noise sounded very valve related, but I adjusted the valves ad that did not help, I swapped injectors and that did not help so then I know that this was a mechanical problem. As bad as it was I was really lucky that it was such an easy fix. But in a diesel the first thing I would expect to cause a knock is something fuel related especially if it goes away when coasting. Check your injectors before you think the worst.

Has anyone else encountered a problem like this with the 617 turbo engines? The engine compression is good with around 400-410 psi across all cylinder and the oil pressure is good but this is a high mileage engine. The car has 352,000 and according to the original owner this is the original engine. Well this was my first experience with a Mercedes Diesel and I must say that I have grown a respect for them. These engines are really built well.

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1993 300D 2.5 Turbo (blue/ blue tex)
1991 350SDL (White/ Gray leather)
1983 300TD Turbo 5-speed manual (Green/ Beige)
1985 300SD (Black/ Black Leather)
1985 300TD (White/ Green Tex)
1980 300SD (Astral Silver/ Black Leather)
1990 560SEL (White/ Gray Leather)
1993 300SD (Black/ Black Leather)
1967 200D (Green/ Beige Tex)
1969 300SEL 6.3 (Moss Green Metallic/ Green Leather)
1975 300D (Astral Silver/ Green Tex)
2001 Ford Excursion Diesel