Air Conditioning pulley noise

[moonunit100]

Hi everyone. I'm hoping someone out there can help me with this one.
I have a 350CLS 2005 model that has re-developed a noisy sort of whining/bearing sort of noise. The last time I heard this same noise I was able to rectify it by tracing it to and replacing a guide pulley that the serpentine belt goes round.
This time I've traced the noise to the air conditioning compressor, it seems to be the pulley rather than something internal to the compressor itself. The noise stays the same whether the air conditioning is on or off, blowing hot or cold. Also, the air con operates with no problems.
My question is, does anyone know if the pulley on the compressor can be replaced on it's own or will the whole compressor need replacing?
The pulley has the manufacturer 'Denso' stamped on it but I can't see any other information on there. It has a central bolt with three holes surrounding it, can't see anything of note behind these holes.
Also, if the pulley can be replaced on it's own, is it simply a case of removing the central bolt or is it a more complex operation?
I've found a guy on eBay selling what appears to be the part I need, he's called atp-spareparts. He's in Germany and the title of the listing is 'Belt Pulley Compressor A/C Mercedes CLS C219 04-10 E-Class W211 S211 C207 A207'
Can anyone help?
Thanks in advance.

 

[Tuercas viejas]

Yes I can help.
This is a Denso compressor , a common fitment on many car brands.

The pulley & bearing assy can be replaced in isolation since it sits on the tubular nose like extension on the front housing.
To gain access to it first you remove the 6 mm end bolt (10mm wrench/socket size) and remove the clutch plate. Caution.
There is a thick washer behind it that is a clearance shim., Important for the setting of the clutch air gap. (Don't lose it or them)

The actual bearing and pulley assy can then be accessed with the clutch plate removed. It is held in place by a large circlip or retention snap ring. Hence you will need a pair of meaty snap ring pliers to remove that clip whereupon you can slide off the bearing and pulley arr" disconnecting the electrical socket for the clutch magnet if necessary. (Obviously you must remove the belt to do this !)

Just a note!
Be mindful of the fact that serpentine accessory belts don't last forever and need periodic replacement. The poly grooves wear down to a point where the belt will slip silently over heating pulleys and their bearings, including the alternator sprag clutch pulley. The benchmark is about 100,000 miles where
the guide belt pulleys and tensioner should be replaced.
All the best
Tuercas viejas

 

[moonunit100]

That's great, thank you very much for the reply and especially for the information.