Hello everybody,

Brand new owner of a 1984 300D here.

So far I'm loving the turbo diesel. The car has a lot of miles (280K) but it's in fairly good shape.

I'm slowly sorting out things that need to be sorted out for it to be a daily driver.

I do have one question for the more seasoned owners: when rolling and ONLY when rolling, the car makes a noise. It's not unpleasant, definitely not grinding or anything like that, it just feels out of place.

I have revved the engine in neutral when stopped, the noise is absent.

I have put the car in neutral when rolling along at 40mph or so and the sound is present.

It feels like it's coming from the front of the car and it sounds a little like a muffled supercharger but not as whiny. It's definitely NOT the turbo whistle.

Can someone shed any light on this?

Here's a (bad) video of it, especially the last 5 seconds. It's not quite a whine, maybe a drone? I'm not sure how to describe it ...

No video.

My car made the strangest noise I've ever heard. Kinda like a cat purring but with a squak in there. Or maybe two pieces of rubber rubbing together. It literally sounded like something a four year old would do to annoy you.

Turned out to be the speedo cable. Little grease and it went away.

I would go through all the checklist and turn the radio up if the cars ok.

Video here:

https://youtu.be/VEW63-rRrLw

If the noise changes significantly when cornering I'd say a wheel bearing.

Rgds,
Chris W.
'95 E300D, 441K

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Objects in closer are mirror than they appear.

change wheel bearings now if your thrifty (inner and outer bearings and races)
or wait and spend more.
mine sounded like that and were ugly
now new smooth and quiet

No sound in the video. At least on my iphone 5 through tapatalk.

Does it sound like a bearing? Are you sure its in the front? I ask because I once had a bad input shaft bearing in a trans, but while driving I swore it was coming from the back right wheel. I threw parts at it for days. And nothing worked.

Its good maintenance to pull your bearings to clean and grease. You can check run out while you are in there with a dial indicator. The bearings may show some wear marks or blueing from heat. Its pretty damn hard to tell the condition of a bearing.

As a test you can simply pull the cap and mash some grease in there.

A proper video may help, but sometimes its nice when you know a good mechanic that you can drive around the block and throw him a 6 pack.

Last thought, I like to check my bearings with a laser temp gauge to spot problems. They are pretty cheap now days. You can go over all the car.

It depends on weather, but on a 70 degree day anything over 100 degrees presents a possible problem. But that is an extremely loose statement. The diff can run that high.

The sound is faint, but noticeable. IMO too low a pitch for a bearing, but checking/replacing can't hurt.

If possible, roll the car down a hill with the engine off to perhaps help locate the area in question. Be very careful of course.

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83 SD

84 CD