faulty alternator clutch?

[BSF Whitworth]

Hi guys. Today at my local stealers I reported a noisy tickover on my C220 CDi. Observation showed an alternator drive belt with lots of "flap" on the top run.

Later I got a phone call to say that I hade a faulty clutch on the alternator.
(quoted £750 net for a new alternator as "clutch is not replaceable as separate")
Are these guys pulling my wire or what?:-

I asked to talk to the mechanic and spoke to a guy who wouldn't admit any qualification, but had been on a course. He explained that the clutch receives pulses from some sort of control unit to reduce drive to the alternator by slippage. This unit was worn and thus noisy.

Anyone heard of this? In 40 years looking after motorbikes and cars I never heard other than direct drive to an alternator. Since the alternator is functioning correctly , with no warning signals, I was not going to authorise any swappeage. I was however chargeed £70 for diagnostics.
ps I could buy the logic for limiting the alternator revs at high engine speeds.

 

[type49]

What a load of cobblers! The clutch is replacable & can be done without removing the alternator. There is a special tool required that they obviously don't have. The description you give does sound like the clutch. Does it also seem very harsh when switching engine off, as though it stops too quickly?

 

[bigasotonuk]

Hi
Same as you m8 never heard of that before, i would of come to the same conclusion that he was pulling your p****r. Just for information what year is your car? (other people will ask)
Only clutch on the belts i,ve ever heard of is on the air con pump.
Iwonder what the more knowledgable members of the forum think?

Try inputting your vin number on this Russian web site you maybe able to identify the so called "alternater clutch".


http://www.detali.ru/cat/oem_mb.asp

Post how you get on

 

[bigasotonuk]

What a load of cobblers! The clutch is replacable & can be done without removing the alternator. There is a special tool required that they obviously don't have. The description you give does sound like the clutch. Does it also seem very harsh when switching engine off, as though it stops too quickly?

Well i,ve never heard of that we all live and learn

 

[television]

Sorry but I will stick my neck out and say no such thing as a clutch on an alternator.

The delivery rate is controlled by the regulator that recieves its info from the exciter wire.

The alternator is only ever replaced when the bearings or coils fail, and that is hardly ever and very rare. the £20 reg pack is all that is required should the charge rate stop.

Noise on the froint end of the engine is always the idler.

Malcolm

 

[230K]

Hi

Yes it is a free wheeling pulley, and they give problems. It is just like the pulley on the rear wheel of a bycycle, free-wheeling in one direction.

Lots of cars have them now apparently.

Read my post on the subject here.
http://www.mbclub.co.uk/forums/showthread.php?t=28134
and here im McCool300TD
http://www.mercedesshop.com/shopforum/showthread.php?t=164552

And television take that neck of yours in stop sticking it out!! LOL

230k

 

[type49]

As for as I'm aware, all cdi engines have these ( certainly from cdi3 onwards )& not on any petrols.
AS 230k says, they are a one-way clutch

 

[Cnics]

"BSF Whitworth" This is very interesting to hear.

http://forums.mercedesclub.org.uk/showthread.php?t=23698

Is a post i made this evening about my Sprinter 311cdi (same engine). From what you have said it appears to be doing the same thing.
I'll assume that when you lift the revs above tickover (even by a small amount) the noise goes away.

After the reply i had i have had another listen and a look (all be it under torch light) and the belt appears to be "flapping" very slightly. I have also noticed (just this evening after some extra tests) a slight slipping (noise) on full lock. A sign the belt is ready, but the knocking shows something on top of that.

I think you'll agree it sounds very similar. I shall be going in to Merc in the next couple of days for some unrelated parts so will get them to have a look whilst i'm there and will report back.

Rob

 

[television]

A free wheel is not a clutch and never has been, it is an MB device and not part of the alternator. Sinse the car runs on the alternator and not the battery this has nothing to do with the charge or charge rate.

Malcolm

 

[230K]

A free wheel is not a clutch and never has been, it is an MB device and not part of the alternator. Sinse the car runs on the alternator and not the battery this has nothing to do with the charge or charge rate.

Malcolm

Come on now Malcolm i was only teasing. Dont be getting cross, just light hearted banter.

230k

 

[television]

Come on now Malcolm i was only teasing. Dont be getting cross, just light hearted banter.

230k

I know, thanks, I study all of the altenator updates from Bosch, I wish that they could include special installations like this, it does give answers though to noises in the front end, I am always pleased to learn.

thanks, Malcolm

 

[230K]

Hi

The pulley is a free wheeling pulley it works in one direction only and slips in the other.
What happens to these pulleys is that they start to slip in both directions intermittently at first and when it does it affects the charge rate.
Maybe most people just change the alternator when this happens but as a Charterd Engineer i am inquisitive and realised the problem is really quite simple.
The pulley looks like a normal pulley.

230K

 

[BSF Whitworth]

car registered 2001 and done 50k miles
Thanx 49 and 230k top info.
Will check freewheel on switchoff and endplay
drive must be ok as no warnings.

thanx television, I think you probably nailed the noise cause, will check tensioner.

Wouldn't have thought there was any more stress on drive belt on spin down than on spin up except praps on emergency braking. I suppose its more energy efficient to freewheel, although seasoned engineers should have forseen reliability and service lifetime problems was the tradeoff.
Hmmm Merc. might get some feedback here.

 

[type49]

Did you find the problem?

 

[battwell]

alternator bearing noise. sprinter , mercedes

ive had these do the splits on me twice in a million miles on my sprinters. the spag clutch or one way bearing on the alternator pulley or rather inside it makes a clicking or squeeling noise as it gets worse. it can be replaced. quoted £32 from mercs for the part. if left they seize totaly and snap off leaving you beltless and un drivable. fix it before that happens. see my other posts on sprinter servicing.

 

[BSF Whitworth]

that flapping belt

further report. Had a new water pump and tensioner unit. No change in tickover noise and belt flap. But now when I press on the belt top run, I see the tensioner pulley moving.
MB dealer diagnosed alternator pulley faulty which is causing the noises etc.
No luck finding someone to change alternator pulley. MB Dealers want to swap assembly including alternator. Others offer recon. alternator assy.
Since all is silky above 1000rpm and alternator charging ok I am sitting on it for the time being. Silicone spray gave minimal improvement.


cheers BSF Whitworth

2002 C220CDi 59k

 

[Sprint'n'Go]

further report. Had a new water pump and tensioner unit. No change in tickover noise and belt flap. But now when I press on the belt top run, I see the tensioner pulley moving.
MB dealer diagnosed alternator pulley faulty which is causing the noises etc.
No luck finding someone to change alternator pulley. MB Dealers want to swap assembly including alternator. Others offer recon. alternator assy.
Since all is silky above 1000rpm and alternator charging ok I am sitting on it for the time being. Silicone spray gave minimal improvement.


cheers BSF Whitworth

2002 C220CDi 59k

Had this alternator problem on my sprinter and merc fixed it under warranty. I am 99% sure they only changed the pulley! It could be worth talking to a Merc commercial dealership. I am sure they won't work on your car but if you delivered your alternator to them off the vehicle they might do it? The 2150cc CDI engine is fitted to 97% of sprinters so they must fix these all the time.

 

[dibdib]

you should not pay more then £75 pound for parts and 1 hours labour so total cost shoud be no more then £150-160 pound.

 

[50sflash]

Hi we have had a few cars where the multi belt is jumping at idle and have found on some occasions that the problem has been the pulley on the alternator dragging the belt, we install a new pulley with alternator still in vehicle, refit the belt, and job done,These pulleys are known as a clutch (why I'm not sure). You will need a special tool to remove this & I know the Snap-on tools now provide these. Good luck John.

 

[television]

Reading all of these pulley post,My thoughts would be to convert over to a normal pulley,they only use this free wheel type on a couple of cars in the range, and it seems that their life is very short.

Malcolm