This happened to a friends' '85 190D. He bought the car at auction for $600, with a perfect body and interior but the broken vacuum pump was laying in the trunk. He brought me a used pump to install but he didn't want to do any major engine dissassembly. I told him he was taking a gamble if the P O didn't get all the old fragments out. The car ran flawlessly for 3 weeks until something wedged between the gear / chain and timing cover, breaking out the chunk that holds the serpentine fanbelt tensioner. The car still runs but can't be driven. I agree that a belt driven pump would have been better. I've gone over 160,000 miles in my '87 Isuzu pickup with very few problems but it's gas, not diesel. Isuzu sold far fewer small diesels here than Mercedes so parts may be a problem. Also, I believe, the small Isuzu diesel (like my gasser) uses a timing belt which must be changed regularly or bad things will happen!

Happy Motoring, Mark

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DrDKW