Pulley wobble clk

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KP090

Active Member
Joined
Oct 31, 2012
Messages
70
Car
Mercedes 06 CLK 280 Sport
Hi guys,

I have a 2006 CLK 280. Over the last week or so I’ve heard my car making a strange noise similar to sounding like a scooter when I accelerate or reverse and I believe it gets more prominent the faster I go.

I opened up the bonnet and notice one pulley wobbling while the car was running and stationery.

I’ll upload the video from YouTube and I hope it works so everyone can see what I’m talking about.

Is it a serious issue that I need to get it looked at straight away and fixed? I’ve got a hour and half journey from maidenhead to Coventry next week so getting worried and short on time.

Any help would be greatly appreciated.

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Thank you!!
 
The only movement I can see is the belt tensioner pulley, the black one on the right.
That will move to mentain tension of the belt.
Looks good to me.
 
Sorry I forgot to say with the video embedded in this forum its hard to see what is moving so if you can view it properly on YouTube then it will give a bigger view and be more clear to see.

It’s the pulley on the right hand side, you can see the silver part moving, is that normal?

Not sure why the car whenever I accelerate or even in reverse sounds like a scooter though?
 
The belt tensioner will move slightly under normal operations.
There is a background whine that may be a pulley bearing on the way out. Remove the belt and check each one.
Does the "scooter" noise only happen for 15 seconds or so after startup ? It might be a siezed alternator pully clutch. This does not usually fail further in a catestrophic manner !
 
Not sure why the car whenever I accelerate or even in reverse sounds like a scooter
Emergency brake cable touching the prop shaft ?
 
The belt tensioner will move slightly under normal operations.
There is a background whine that may be a pulley bearing on the way out. Remove the belt and check each one.
Does the "scooter" noise only happen for 15 seconds or so after startup ? It might be a siezed alternator pully clutch. This does not usually fail further in a catestrophic manner !
Thank you so much for your reply!

That background wine has always been like that, I had one of the pulley’s changed last year as it was more of a whine an squeak but now it’s a lot quieter.

The scooter type noise happens all through a journey a make not just when I start it up of first 15 seconds.. even half hour later you can still hear it when accelerating with the radio off.

I’m a bit worried as I saw this wobble and the noise so thought it must be to do with that.. as you can tell I’m no expert lol
 
How old is the tension pulley? If original replace with a new one.
They can let go without warning and shred the belt causing more problems.
This happened to my CLK M272 motor.
 
I have had the tensioner pulley changed last year.

I had a mechanic look at it and they took the belt off and spun the pulleys. Said tensioner pulley was fine but the alternator, water pump and idler pulley were culprits with the alternator being the main cause of the noise.
While revving the car with the belt back on it make a loud grinding squeak noise.
Was quite £850 for new alternator, water pump, idler pulley and belt.

Does this sound correct in terms of the problem and price?

Thank you
 
I have had the tensioner pulley changed last year.

I had a mechanic look at it and they took the belt off and spun the pulleys. Said tensioner pulley was fine but the alternator, water pump and idler pulley were culprits with the alternator being the main cause of the noise.
While revving the car with the belt back on it make a loud grinding squeak noise.
Was quite £850 for new alternator, water pump, idler pulley and belt.

Does this sound correct in terms of the problem and price?

Thank you
I think you got ripped off for a new alternator. It's the clutch in the pulley that fails and that can be replaced separately for +_40gbp.
 
I think you got ripped off for a new alternator. It's the clutch in the pulley that fails and that can be replaced separately for +_40gbp.
Is there a way of knowing whether it’s actually the alternator and water pump failing rather than just the clutch of the pulleys that you are saying?
 
Is there a way of knowing whether it’s actually the alternator and water pump failing rather than just the clutch of the pulleys that you are saying?
it's a one way clutch on the alternator shaft. It is an easy diagnosis. I cannot comment on the water pump bearings, but they do fail
 
it's a one way clutch on the alternator shaft. It is an easy diagnosis. I cannot comment on the water pump bearings, but they do fail
The mechanic said the noise was definitely coming from the alternator, when revving the car was making loud screeching type noises..
water pump he said it can wait but soon will have issue has there’s play in the pulley of the water pump..

I haven’t had any major issues with the car till now and didn’t expect such a big cost, I can ring them tomorrow and say change only the pulley for the alternator (maybe he didn’t know that you can buy the pulley for alternator rather than the whole alternator?)

Is there any signs I would know myself if the alternator was actually on its way out as well as the water pump?

Water pump - the car temp is fine no coolant leaks

Alternator - no battery issues, my command sat nav unit sometimes doesn’t turn on so have to take the fuse out and put it back for reset then it’s fine.

Other than than I don’t really know..

Trouble is I need my car asap as going on a long journey and the merc specialist I use are fully booked till next month.

When revving the car did make a major loud screech that sounded worrying..
 
The screech sounds like the clutch pulley, they normally get noisey on the overrun. The cost difference between a pulley and an alternator is major money.
 
The screech sounds like the clutch pulley, they normally get noisey on the overrun. The cost difference between a pulley and an alternator is major money.
Are there any obvious signs that it may actually be the alternator as well as the clutch pulley for it?
The mechanic was certain it’s alternator but I’m guessing he may not have known you can buy the pulley for it separately or he knows that the actual alternator is on its way out altogether?
 
With the belt off you should be able to feel if the clutch is on the way out. It should allow the rotor to free wheel one way and lock up in the other rotation. If it crunches or clicks it's shot.
 
With the belt off you should be able to feel if the clutch is on the way out. It should allow the rotor to free wheel one way and lock up in the other rotation. If it crunches or clicks it's shot.
I think it definitely was clicking when he was spinning it round with the belt off but does that the clutch is only gone or the whole alternator as well?

With the water pump pulley there was a bit of play and the idler pulley too.
 
Spoke to Mercedes parts and they have the pulleys available for the alternator and the water pump so I don’t think the garage I took my car knew mercedes do it seperately rather than buying whole new unit.

this will definitely save me a big chunk of money and hopefully fixes the issues.
 

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