The engine in my newly purchased 1999 300D is producing a whine on the driver's side. I'd just like to know whether it's anything that I should be worried about and if it's correctable. The whine gets higher in pitch and louder as the rpm's increase, and is particulary noticeable, at least to me, between 1600 to 1900 rpm from inside the car whether the car is standing still in neutral or cruising down the road. I don't think it's the turbo unit which is located on the passenger side of the engine and I think produces a higher pitch sound which is almost unnoticeable.

The engine runs smoothly all the time and doesn't hesitate on acceleration, and doesn't smoke unless I really push it, so I don't beleive anything major is wrong. But I've heard so much about noisy fuel injectors on diesels I was wondering if it could be these making the noise. I don't know what noisy injectors sound like. Or, it could just be the nature of the beast.

We've also had a 1993 300D in the family for some time now and that car doesn't make the same whining noise.

Your comments will be appreciated. Thank you.

Turbo whine?

I have a 99 E300 and can hear that.

Did you listen to it with your head in the engine compartment? If not, you need to do that to pinpoint the source of the noise. If it's not the turbo it could be the injection pump or one of the belt pulleys. My car has a subtle whine only at idle and I think it's the IP but I'm not worried.

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2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

Thank you for your comments "bmisf" and "dieseladdict". I did listen under the hood with someone pressing on the accelerator pedal and the whine is definitely coming from the driver's side of the engine, not the turbo side. At idle speed I can't hear the noise. It's only in the range of about 1600 - 1900 rpm it's more noticable to me, but everyone's ears are tuned differently and it may be more noticable to someone else at a different rpm.

The car is in "excellent" condition and I have service records to prove it was well taken care of. But I did splurge and take it to a MB dealership to have it serviced a couple weeks ago and also had the 25 point inspection performed. The report I got back was that they couldn't find anything other than a couple oil changes and oil filters that it needed and that it was in great condition.

Any further comments would be appreciated.

Check the power steering fluid level.

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Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References

I just saw that you reposted this in Tech Help. Did you check the power steering?

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Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References

Hello Rick,

Sorry about the double post. I wasn't sure if I should do that or not, so I took a chance. I thought maybe the audiences may be different under Tech Help and Diesel Discussion.

I did check the power steering fluid level. The fluid was very clean and the level was at the second indicator line from the top on the measuring stick (in the cap).

At the suggestion of someone else, I used the metal handle from my carpet sweeper, and with the handle end against my ear, probed around under the hood with the engine running and a helper adjusting the rpms up and down. After several trys at various locations including the turbo unit, the only place so far where the frequency of the whine matched what I was hearing from the driver's seat, was at what I beleive to be the injector manifold - the one on the driver's side of the engine with all the small diameter brass tubes coming out of it. Actually, the noise was loudest at a cast part just to the rear of the manifold. It may have been a pump housing or something else. I'm not familiar with the engine.

From the passenger compartment, the whine is definitely more noticable from the driver's seat than from the passenger's side. Strange. Maybe I'm missing some insulation on the driver's side somewhere.

Jack
Phoenixville, PA

Well, this is all interesting. Mine has been doing it for a while too. However, it doesn't do it when it is in neutral. I'll be going along slowly and won't hear the noise. Only when I then gun it does it does the noise kick in and sound like a high pitched spinning sound. It drives me crazy! If I'm going one speed sometimes just a little more pressure on the pedal will activate the sound. When I back off just a hair it stops. High piched whirring/whine/whistle. I have joined the club. If someone could provide any more help, that would be great. I thought it might be the transmission fluid pump not getting fluid, but I checked my levels and they were ok even though I know the front seal is leaking.

Someone else chased a similar problem a while back and eventually narrowed it down to what he thought was the oil pump. I don't recall if he did anything about it or decided to put with it. I have a similar issue and had a Benz service manager listen to it with a stethascope (sp?) just yesterday. He had never heard this before (98 E300TD). He thought maybe the valve train or an injector, but added he wouldn't wory about it. I'd also be interested if anyone else has had similar problems and what the remedy might be.

Well, my '99 E300D is still whinning away, but I'm getting used to it now. It's not all that irritating. However, I had it to the MB Dealer Service Shop the other day for an oil change and serpentine belt change, and asked their diesel expert to test drive it and listen to the whine. He claims he did this, but didn't hear anything unusal. Said that what I was hearing was turbo whine and not to be concerned with it. I'm not exactly buying this at the moment, because I can faintly hear the turbo whine now and then coming from the passenger side of the engine compartment. It's a higher pitch than the noise we're talking about, and almost unnoticeable. I had another MB mechanic listen to it about 6 months ago and he also claimed it was nothing unusual. It must be an age thing though, because I doubt very much these cars made this noise when they were brand new. I've been using the Rotella T motor oil per the MB diesel mechanic's suggestion, but just switched to a synthetic oil and haven't noticed any difference in the noise. But, the engine runs great and fuel milage is still good so it probably is nothing to worry about. However it would be nice to know what's causing the noise if we can ever truly pin it down.

This whine that were talking about is not in our imigination, it is coming from the driver's side, and occurs at the 1600-2000 rpm range. I have a little more volume on this when it's cold even though in the same rpm range. Once it warms up the whine levels out at the same pitch in this range and with road speed (60 +) it's barely noticeable. Driving around town it's always there and I am trying to get used to it, but don't like it much. I'm really hoping someone could shed some technical light on this. The shop boys at the dealers don't seem to have a handle on this one yet.

Jack525--You might also do a search under "engine whine." e300nocash posted some interesting information on this problem in Dec. 05 and his mechanic was the one that thought it might be the oil pump and had heard of this issue before. I'm going to FAX his info. to my service manager and ask him to check his resources. Looks like there might be an updated oil pump on this to resolve the problem.

You should at least try an eliminate any of the serpentine belt driven accessories as the cause, (i.e.: Alternator, AC compressor, Power steering pump, etc.) This will also test the belt shock and tensioner as possible causes.

You do that by removing the serpentine belt and driving the car without the belt for a few minutes. See if the noise is still there.

Phil

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'95 E300 Diesel, 264,000 Miles. [Sold it]

Van Helden - - I had previously used a long metal tube held to my ear to probe around under the hood while my assistant operated the throttle from inside the car. I probed the turbo unit, all the rotating stuff that the serpentine belt drives, and many other parts of the engine that I could reach. The whine noise was almost none existant until I got to the small manifold on top the injection pump housing on the driver's side of the engine. The noise got louder as I moved the probe toward the rear of, I guess, the housing. I'm not sure if that whole assembly is part of the injection pump, or something else. I'm also not sure where the oil pump's located, so I don't know if the elevated noise volume was in the vacinity of the oil pump or not.

Anyway, it'll be interesting to hear what your MB mechanic comes back with. So far I haven't gotten anywhere with MB Dealership mechanics. I also had it to an independent MB mechanic who couldn't come up with an answer either.

Jack525
Phoenixville, PA

Nothing new to report, but I did send all responses to my service manager and he never responded until I called him 4 wks later. He said he could find out nothing on this issue. So much for that. NOW, someone did mention power steering and I thought nothing of until I started asking questions about why mine was so tight. The E series does not have the variable steering so something is up with that. Another MB mechanic thought a tight balljoint or something really tight in the strearing box. Any ideas on either issue?