w124 e220 coupe - whirring grinding sound from under car

[ladd220]

Hi Folks,

I hope someone can help... i have a 1996 w124 coupe. I posted a thread earlier this year explaining that i have a noise coming from under my car when its in DRIVE or REVERSE and the brake pedal is pressed. It was thought that it might be a vacuum leak causing the whistling/whirring sound. but it wasn't.

The problem has now progressed and i know how to replicate the sound.

At first the sound would only appear when the ambient temp was low. when the car was in D or R, with the brake pedal pressed.

Now, if i drive through a puddle, the water is splashes onto some sort of moving part or flyweel underneath the car. when this happens i get a combination of very loud grinding/screeching sounds, then a whirring, which turns into a high pitched whistle and then fades away, as if the water has gotten into something and has then been driven out by the movement. If i'm moving, the noise is minimal. The noise is at its loudest when i slow down using the brake. If i put the car into neutral, the sound stops. and will return when i selct D or R again and have the brake pedal pressed.

The sound is made regardless of whether the car has been running for a while or not.

My own thoughts are that perhaps the flywheel underneath needs greasing. with the low ambient temp, perhaps there is a build up of condensation, which caused the sound in the early days of the problem. and when water comes up from a puddle, its louder due to more water being there.

Please let me know if anyone has also experienced this before and whether they know what the problem might be. also, if there is a low cost solution to this problem... many thanks in advance.

 

[BillyW124]

Could you have worn out propshaft bearing/couplings?

As this piece is interconected with the shaft and is in sync with gear changes im wondering if its worn out somewhat causing this sound perhaps?

 

[Henry D]

If water splashing up creates the noise I would be having a good look at the auxillary drive belt to see if its in good condition and that the auto tensioner is working correctly

 

[ladd220]

Hi BillyW124,

If the propshaft bearing/couplings have indeed worn out, would i expect to get most noise whilst moving or when stationary?

At the moment, the noise is most apparent when a gear has been selected and i have the brake pedal pressed, so i'm just wondering whether the propshaft bearing/couplings are in motion even though i am stationary...

Henry D, where might i find this auxillary drive belt and auto tensioner? And also, would they be in motion whilst the car is in gear but stationary?

many thanks for your responses,
Ladd220

 

[Henry D]

Hi BillyW124,

If the propshaft bearing/couplings have indeed worn out, would i expect to get most noise whilst moving or when stationary?

At the moment, the noise is most apparent when a gear has been selected and i have the brake pedal pressed, so i'm just wondering whether the propshaft bearing/couplings are in motion even though i am stationary...

Henry D, where might i find this auxillary drive belt and auto tensioner? And also, would they be in motion whilst the car is in gear but stationary?

many thanks for your responses,
Ladd220

Front of the engine by the radiator fan and yes in motion with the engine running regardless of vehicle movement

 

[grober]

My guess a problem with the pump/valves on your ABS ACTUATOR unit. Does your ABS light come on when this happens? [ does it come on when you first switch on the ignition even?] What's you brake fluid level like?

 

[ladd220]

yep, the belt is new and i changed the tensioner and pulley only recently... also, in the early days of the whistling/whirring sound, i checked with the bonnet open, and the sound was definately coming from below the engine. on another occasion, when the sound occurred, i opened my door and half hung out of the car... it was coming from underneath, which is why back then, we thought it might be a vacuum leak...

 

[ladd220]

My guess a problem with the pump/valves on your ABS ACTUATOR unit. Does your ABS light come on when this happens? [ does it come on when you first switch on the ignition even?] What's you brake fluid level like?

Last year, the ABS light used to come on, but a new battery fixed that problem. Otherwise, the light comes on with the ignition and then goes out. It does not come on when the noise occurs. Brake fluid is also ok.

 

[ladd220]

I managed to get a look underneath the car today. In front of the ATF tray (towards the engine) i could see the pro shaft "donuts" high up, and in front of that, a large metal casing with the flywheel in it. At the bottom of the casing there are some vents. My suspicion is that when i go through a puddle, the water goes up that vent and possibly onto the flywheel bearings making the noise until the water has been expelled by the spinning wheel. Thats also the area where the sound seems to be coming from...

Whilst i was under the car, i also checked the shaft going to the diff i was able to turn it with my hand about 1cm each way. Don't know if that could be connected. All thoughts are welcome....

 

[carat 3.6]

It sounds like a worn propshaft center bearing.

 

[grober]

Might be a problem with your torque converter. It's only " loaded up" when the car is in D or R with brakes on since its trying to drive the gearbox which is held stationary by the brakes and propshaft. Possibly worth draining the torque converter to check the condition of the fluid. First thing to do is check the overall autobox fluid level is correct- follow the handbook instructions to the letter to do this. Best done when the fluid has reached operating temp. If this is OK then drain off the torque converter http://www.mbclub.co.uk/forums/howto/23969-howto-change-atf-97-w210.html { not the same car but shows what's involved.} Catch the fluid in a clean container and look for signs of wear- metal particulates/burnt fluid= brown or black not clear red/yellow Measure CAREFULLY how much comes off since you will have to replace this with new or what you drained off if it looks OK. fluid meeting Dexron 2 or 3 will be fine for a 1996 car I favour Fuchs Titan ATF 4000 myself.

 

[grober]

It sounds like a worn propshaft center bearing.

Good Call normally but the Propshaft won't be turning if the car is stationary [ poster is not exactly clear about this]
ps that 1cm backlash is pretty normal BTW

 

[ladd220]

It sounds like a worn propshaft center bearing.

Is that bearing still in motion when the car is stationary?

 

[ladd220]

Might be a problem with your torque converter. It's only " loaded up" when the car is in D or R with brakes on since its trying to drive the gearbox which is held stationary by the brakes and propshaft. Possibly worth draining the torque converter to check the condition of the fluid. First thing to do is check the overall autobox fluid level is correct- follow the handbook instructions to the letter to do this. Best done when the fluid has reached operating temp. If this is OK then drain off the torque converter http://www.mbclub.co.uk/forums/howto/23969-howto-change-atf-97-w210.html { not the same car but shows what's involved.} Catch the fluid in a clean container and look for signs of wear- metal particulates/burnt fluid= brown or black not clear red/yellow Measure CAREFULLY how much comes off since you will have to replace this with new or what you drained off if it looks OK. fluid meeting Dexron 2 or 3 will be fine for a 1996 car I favour Fuchs Titan ATF 4000 myself.

Its definately a moving part that is still in motion even when the car is stationary. If i release the brake pedal the noise is significantly reduced.

Thanks for the great link on changing the atf fluid.

Just wondering about the car being on ramps, i'm assuming the car has to be level when changing/draining the atf - I'll try it once i've bought a new gasket.


greame, The torque converter suggestion sounds quite accurate, but not sure how water being slashed upwards could affect this...

 

[carat 3.6]

Good Call normally but the Propshaft won't be turning if the car is stationary [ poster is not exactly clear about this]

Ahh I missed that, in that case I agree with you about the torque converter being suspect.

 

[ladd220]

I've read something about a "Solenoid Valve" linked to a torque converter... I have no idea what it is or what it does, so apologies if anything comes across as real dumb...

my understanding is that a solenoid valve is somehow connected to a torque converter. If that is damaged, or has become worn, then maybe its letting in water, hence the noise...

what do you guys think?

 

[ladd220]

I've still got this problem... Any other suggestions would be most welcome...

Thanks in advance.

 

[lothtig]

Nike High Heels

http://willieandthehandjive.com/hom...icleseven.info/the-invention-of-nike-air-max/

 

[bolide]

It can't be anything aft of the gearbox because it happens when the car is stationary

Why (and how) is the noise produced / started when the brake pedal is pressed? And why only in D and R and not P?

One thing that happens with W124s is that engaging a gear tends to load up the gearbox, couplings, prop & diff. One some cars you can even see the rear wheels move back & forth in the arch when shifted R - P - D. This effect changes if the car is held on the handbrake or footbrake

My theory is that the engine mounts have collapsed and the noise is caused by something rotating or touching because the engine shifts around when put in gear

Or the car has a broken flex disc

Take it to a specialist

Nick Froome
the independent Mercedes Estate specialists

 

[ladd220]

It can't be anything aft of the gearbox because it happens when the car is stationary

Why (and how) is the noise produced / started when the brake pedal is pressed? And why only in D and R and not P?

One thing that happens with W124s is that engaging a gear tends to load up the gearbox, couplings, prop & diff. One some cars you can even see the rear wheels move back & forth in the arch when shifted R - P - D. This effect changes if the car is held on the handbrake or footbrake

My theory is that the engine mounts have collapsed and the noise is caused by something rotating or touching because the engine shifts around when put in gear

Or the car has a broken flex disc

Take it to a specialist

Nick Froome
the independent Mercedes Estate specialists

Thanks, Nick,

What about when i go through a puddle? The water splashes upwards, after which the noise becomes a grinding sound, then it becomes a smoother high pitch sound and then disappears...

Would the possibilities you mentioned still cause the same sounds?

I will also get a specialist to take a look at it...

Many thanks.