C55 whine

[RSTurbo50]

What is that slight whine when accelerating? It's not got a supercharger I know that but you can still hear something. Is it normal and does anyone know what it is?

 

[whitenemesis]

Differential?

 

[brucemillar]

They are by design whiny, belty engines. Very loud whine at start up. It may well be just normal. Have a good listen with the bonnet up and the engine up to temp. Do not get your neck tie caught up in the belts.

 

[Will]

Check the idler on the poly-V belt at the top of the engine. The bearings often fail and the plastic cracks up - cheap to replace.

 

[whitenemesis]

Shouldn't hear anything but exhaust growl when accelerating.

 

[RSTurbo50]

It's only a very slight whine nothing major. Reading up on it via various forums many of them seem to have a bit of a whine to them so I'm not too worried about it...

 

[Grovsie31]

Mine doesn't whine when accelerating and upto temp. Does have the cold start whine like all M113 V8's seem to have.

 

[gazz]

I'm on the verge of replacing my air conditioning compressor, as I think that is the source of it. I had a late 209 clk in the other day with a faulty compressor and it made the same noise at start up. New compressor fitted and the whine has gone. The facelift cars have a clutchless compressor that runs all the time, so you can't isolate it by switching it off.
I might wait a month or two to see if the clk has the whine return as the new compressor settles down...

 

[RSTurbo50]

Ask said I'm not worrying about it as its maybe just a characteristic of the engine..

 

[edc]

I have the usual whine at start up on mine but don't notice anything significant when on the move. However with a rear decat you probably wouldn't

 

[RSTurbo50]

It's not a loud whine when on the move its just a very muted one but if you listen it is noticeable. It may just be me though. Got my car booked into JP Exhausts in Macclesfield in August for a silencer delete. Looking at £250 though I'm told..

 

[Grovsie31]

250quid just to remove the silencer is pretty expensive.

 

[RSTurbo50]

He said it would be 3-4 hours work at £60 per hour plus VAT

 

[Grovsie31]

4 hours to remove an exhaust, cut out a piece and weld in some stainless and bolt back on...........

 

[Howard]

Olly did mine in an hour

 

[RSTurbo50]

Who is Olly?

 

[BlackC55]

Me

 

[BlackC55]

Your whine will probably be the AC compressor. They are common for it.

 

[Grovsie31]

^ Olly is da man! Bit of a treck for us midlanders though.

 

[E55BOF]

My '04 E55K (805 build) whines quite noticeably all the time, though it's not obtrusive inside the car, and over 1500 rpm it's inaudible inside. It's irritating, though, and I'd like to be rid of it. The '03 E55K didn't do it, nor did the W210 E55 before that.

It's not the idler pulley - I replaced that (awkward little job...). It's not the power steering pump - WG MB replaced that. It's not the blower - removing the drive belt makes no difference.

It seems to be coming from low down on the passenger side front, so the aircon compressor would seem likely to be the culprit. Switching off the aircon makes no difference. Switching off the heating/ventilation completely also makes no difference.

Do I have a permanently-engaged aircon compressor on an '04 W211?