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MBGuru, Mercedes Mechanic
Category: Mercedes
Satisfied Customers: 594
Experience:  25 years on MB, diagnostic tech and trainer.
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Hello, I have a 1992 Mercedes 300D 2.5 turbo diesel. Engine 602.

Resolved Question:

hello, I have a 1992 Mercedes 300D 2.5 turbo diesel. Engine 602.962 Model 124.128   I removed the five fuel injectors and had them rebuilt (bosch nozzles). I just reinstalled them and the engine runs fine but it appears to be running considerably louder at idle. It drives just fine with no apparent clacking sound (which is only at idle) Is there anything that can be done to reduce that typical diesel engine clacking sound?

Last week I posed this question and tried two quarts of ATF as suggested and it made was no difference. I've read that adjusting the injection pump timing might reduce the loud clacking diesel sound at idle. What do you think? If timing is possibly the problem could I adjust the timing or should I take it to a repair shop?
Submitted: 9 years ago.
Category: Mercedes
Expert:  MBGuru replied 9 years ago.
Run it, those engines take time to fully expell the air. I've had them be loud for 100 miles. I always tell people to put them on the highway at 70 or so MPH for 30 miles, then see if they quiet down.

Also, the wrong nozzles can cause this. Be sure all the plastic fuel line supports are in place as well, otherwise, it will break lines and leak like a sieve.
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