Ok, so here is my problem, a few weeks back the car started to make a droning noise accompanied by a vibration, it only happens when the car is at idle or just above it (max ~1300 rpm) any higher and it goes away

At first the noise only occured when the engine was cold. Lately it has started to get worse. The droning sound now occurs even if the engine is at normal operating temperature. BUT it's INTERMITTENT. Sometimes it does not go away for a good 20 minutes, sometimes it's not even there for the entire drive. AND it is ALWAYS accompanied by vibration that come and go with the droning noise. And it seems to come from the front of the car. Or atleast from ahead of me and not behind.

The car has no CEL. It happens when the car is in Park, Gear or Neutral. But only at idle or a bit above it.
I have no clue what it is, but it is scaring the crap out of me.

I've searched the forums, but have manged to find nothing that might explain this.

So, any help is appreciated.

Also, any chance it might the belts? I will be changing them tomorrow because the are all cracked up like no tomorrow. Any advice on that is also welcomg.

 

Yeah I am having this problem too, but I noticed that it vibrates and creates the strange drone sound when its in gear the most and it also lasts the longest when in gear.

But whenever it vibrates, if I have my foot lightly on the gas but not actually stepping on it I can feel it. But the problem is that I cannot hear it in the engine bay. You can only hear it inside the car

I honestly have clue what it could be, I guessed that it might be something connected to the throttle cables, since I feel it in the gas pedal but so far I'm clueless.

 

exhaust leak maybe?

 

Maybe, will look under the car tomorrow when changing belts but, will an exhaust leak case it to be intermittent and create a vibration?

 

I'd say so, I have a slight crack on the welding around my resonator and the pipe and its vibrating and almost sounds like its surging but its because the air doesnt seem to be able to all escape through the crack. I'll find out once I get it fixed or replaced.

 

Hmmmm, if it is the exhaust that might explain why I have been feeling like the car does not have as much power as it should (I got my father's '97 in prestine condition to compare to), it might also cover the quick deterioration of the situation.

Anything in particular one should look at when looking for a leak?

 

My 96 5spd has the exact same symtoms. I can hear it in the cabin loud, but barely hear it in the engine comp. Thought it might be air in the steering rack and flushed with new ATF. No change. Its in neutral and gear with clutch pedal depressed. Ill check the exhaust on the ramps. I do notice it starts after 3000-4000 Miles on an oil change, suspect timing chain, however I dont hear it all that loud from the TC itself. Just changed oil this weekend and it went away overnight.

 

I would have guessed the radiator fan, but since you cannot hear it in the engine bay I would assume it is not the radiator fan.

Is your idle set too low? Perhaps raising it would solve your problem.

 

Idles fine, ~1200 cold and ~700 warm. Besides this noise car runs and sounds like new at 256K.

 

Mine idles a bit low, its at about 500 RPM in gear. But the thing is that even at high RPM you can hear it. I mean it sounds like a motor that is connected to the throttle cable or gas pedal is getting stuck and is vibrating trying to get lose or something.

But I think I am going to do the Seafoam thing and see if smoke comes out of any place other than the tail pipe.

 

Havent heard it once since changing my oil four days ago. It was doing it EVERY day for the last couple weeks before changing oil. As Leo stated, it does sound exactly like a bad electric motor growling, and it seems to be coming from the fire wall. Howver, it happens with the heat/AC off. Seems to go away when I turn the AC on, but I think it has to do with the idle speed bumping up. Next time it starts doing it Ill pull my belts just to eliminate the accessories and pulleys, unless someone else wants too now.

Iwill add, This has been happening since I brought the car home a year ago and always goes away with an oil change.

 

Yeah thats what I was thinking a electric motor!

But the strange thing is it always goes away when the engine is hot. Maybe we should start poking around haha

 

OK, did it today when I started the car after work. If it gets predictable soon Ill check some things out. My money is on tensioner and guides though.

 

My car has been making the same noise, the same way. Sometimes I feel it under my feet, but it generally goes away after driving for a while. On a side note, I just changed my water pump and TC Tensioner, so I wouldn't attribute that to the problem.

 

For those that are feeling like the car has less overall power, I'd suggest checking your catalytic converter - it may not cause a code, but it can certainly rob power, cause odd noises forward of it within the exhaust, and cause vibrations.

 

Did you change any of the guides?

 

Any new information on this noise?

I think it might be my IACV or something. I've never taken apart my IACV but I know that its a motor. Could that be the cause?

 

After reading this entire thread I'd rule out the IACV as the culprit. After cleaning my IACV it made squeaking noises as the valve slides within the step motor. I could hear it behind the dashboard while driving slow. With the hood open I can easily pinpoint the noise to the IACV unit.

 

Ah I see but we can't hear the vibrating noise under the hood only inside the car.

Man! The noise is getting louder and lasting longer and longer. I have a feeling that if we leave it alone long enough something very bad is going to happen. Just like timing chain that is starting to fail if we don't fix it and ignore it long enough, DISASTER!

So as of now I can only thing of the blower motor or something INSIDE the car that is making that noise. I went through every fan speed and MODE on the controls and the noise the motor makes when its closing the vents or whatever still doesn't sound like the noise I hear at start up.

 

I had thought but dismissed it as far fetched. AC clutch bearing, harmonics traveling through the lines and resonating from the condenser under the dash?
At this point its not often enough to effectively trouble shoot yet, when it gets bad again I'll remove the belts. Also Im gonna try 10/30 with my next change.

 

I have been using Rotella 5-40 and thats when I noticed the noise a lot. Could oil be possibly the cause?

But today I was messing around with the hoses around the TB like squeezed all of them and checked around the IACV for leaks or SOMETHING that could cause the problem. And when I got in the car and put it into gear I didn't hear the drone noise, and then I heard it once for like a second and then it disappeared the whole trip.

Hmm............ still clueless but I think we are getting somewhere

 

I was googling up our problem and I cam across this Benz forum with a couple members who had problems exactly as we do.

And they concluded that it was the cruise control that was causing the vibration. And that by resetting it they fixed that vibrating noise which you can also feel in the gas pedal.

And for Mercedes their procedure was to put the pedal to the metal and then turn the key to ON or something.

 

What would it be with ours? Doesn't hurt to try I guess.

 

Did you guys ever figure this out? Where exactly do you hear the noise, is there a particular spot / area? Can you post a vid / link please?

 

Yeah it doesn't work, I tried every method to reset the cruise control, even disabling it manually completely. And still the noise is there...

The only thing I can tell you is that you ONLY hear it the loudest in the driver's seat and its the worse when the temp is cool to cold. And it feels like a vibration in the floor on the driver's side. I was in the passenger seat and couldn't feel it or hear it that well but in the driver's side you can feel it.

So my second guess is that from what I heard on Youtube videos, it seems like something is loose. Like maybe a heat shield or maybe a manifold. But the thing is that you cannot hear or feel it in the engine bay its all in the car in the floor area. Oh and a strange thing I've just noticed is that the vibration resonates up to the dash sometimes and so the noise seems like its coming from the dash.

 

I don't think its Cuise control, we have vacuum CC. It wouldn't make that kind of sound. Leo, do you have stock exhaust, if not what have you changed, Mine is stock with all stock shields.
I really think its an internal motor issue.

 

This is just a thought for you guys but have your guys tried the A/C compressor bearing?? Have you replaced it or are you still on your original? Mine has a similar sound and will squeal the minute a drop of water gets on it and can feel the vibrating when the A/C is on. Is this the case for you OP?

 

When mine gets predictable enough to troubleshoot, It was but its better now after oil change still, I will pull the belts and check.

 

Yeah everything about my car is stock except for the outside.

The sound doesn't seem to be the A/C bearing because I can't hear it in the engine bay, and also I don't use the A/C since I have a hole in my condenser and so I am a little stumped.

The thing is that if it was belts, bearings, and other stuff in the engine, I'm pretty sure we can hear it with the hood open and us standing over the engine, but I can't hear any strange noises under the hood ONLY in the car

But I found that the noise seems to die when I go over a bump pretty fast. Like I accidentally hit a speed bump going 35 and it jolted the car pretty good about a week ago and the noise has either went away completely or is too low for me to hear. LOL

 

It's definitely not the belts. I replaced mine not too long ago and the noise is still there.

LOL @ Leo. I think i'll try that tomorrow. =)
If it goes away as well then we can confirm it as something loose. If it doesn't I guess we wait until someone's car breaks and we can tell exactly what it is.

 

[quote=silencecalls;7665211]It's definitely not the belts. I replaced mine not too long ago and the noise is still there.quote]

I meant I'd run it without a belt, to see if its an accessory bearing (ie AC clutch).

 

post a vid of what its doing. Its kinda hard to imagine "droning". and this ONLY happens at idle correct? i assume you checked your air filter to make sure its clean? are all your fluids filled?? i feel like this "noise" is coming from the power steering. next time it "drones" and vibrates, turn the wheel and see if it lessens.

 

LOL I think I fixed it by hitting that speed bump.

But yeah ImmaSquashYou, you have a good point I think I am going to see if I try that when the noise comes back.

I think the best way we can remedy this is when winter comes because on those rainy and cold days the noise is SIGNIFICANTLY louder and lasts longer until the car gets hot.

And the noise is really hard to actually record, I tried on my phone in complete silence and all I could hear after playing it back was the engine idling or nothing at all. Even though in person I could hear the drone. For me the noise comes from the driver's floor and resonates up to the gas pedal. The only way I can describe that noise is like if you have those vibrating head massage things and put it on the table with it vibrating. The noise you hear is the same as the noise I am hearing in the car.

 

I've been wondering about this noise too.

For the last year, I've KIND OF heard it/felt it in the gas AND brake pedal. NOW my mechanically inclined friend can hear it.

Words like "groaning, whirring, gurgling, humming" come to mind to describe it.

The sound is heard while warming up, and disappears when driven for awhile.

The sound is sensitive and varies based on low RPMS. The sound can't be heard while moving more than a couple mph, BUT if you feel the gas pedal you can tell it's still intermittently groaning.

I've thought it may be air in the coolant system, but I've sufficiently burped the car to eliminate that.

I think it's an oil pump bearing or something. I hope I'm really really wrong. But it IS getting worse.

I AM do for an oil change though... By "due" I mean I've probably put 5-7k on this round (synthetic) of 10-30.

 

Update: I've done my oil change, and am unhappy to say that though the groaning isn't as pronounced, it is still there. I'm hoping we can solve this riddle, as I intend to drive my car for the foreseeable future.

I used Mobile 1 fully synthetic 10w-30 high mileage.

 

Same with me the speed bump thing was temporary.

I noticed that the noise started after i changed the oil to 5W-40 and so I thought it might be something related to the oil pump. But yeah I hope someone can come up with a solution.

 

I have a small update, it seems like the noise doesn't go away anymore. And now there is the same noise except a lot quieter that comes and goes when the car is idling whether at a stop light or just sitting there.

I can faintly hear it in the engine bay now too, and I am starting to suspect the A/C bearing. But as usual the investigating goes on!

 

Does anyone here having this problem have a manual transmission? My angle is that maybe this is A/T related....

 

There's five of us describing the same problem, however one of us has a manual transmission. The rest of us it seems have a 95 or 97 GLE.

Here are the active guesses that aren't ruled out:

Catalytic Converter malfunction

Accessory Bearing

Oil Pump related


I'd like to add that from my oil change, I don't feel anything different from before. I don't think our oil types have anything to do with the problem.

 

I think I had the same "droning" noise like everyone else. It really sounded like it was coming from the power steering. I did not have this vibration you guys were having though.
Yesterday I bypassed the A/C, so I picked up a new belt.
I put the new belt on and now the car is quiet as hell. There is no annoying noise coming from the belt anymore.