W202 squeak - A/C Compressor bearing ?

[PJH]

R reg 57,700 miles.
Wifey's W202 has had a squeak for about a month or so. It's coming from the front of the engine but would disappear as she drove off. So it's only there when stationary. I did give a squirt of oil to the back of all the pulleys a couple of weeks ago but the squeak persisted.
This morning I pressed the EC button and the squeak stops and returns when the button is pressed again. So seems to be the A/C compressor rather than the pulley driving it. A/C output is good ie cold.

Is there a bearing that is about to fail ? Or the whole unit ?
Can I lubricate anything to stop the squeak ?

 

[bibamus]

Could be that the belt is loose or worn, the extra load of the a/c compressor running could make it slip or squeak a bit. Try running the car with the a/c on and drip some water on the belt. If the sqeak stops, its the belt.
I have this problem on the power steering belt on my Golf, sometimes its noisy ( squeaking) sometimes its quiet and the noise goes as you drive it. Spash water on it, and it all goes quiet till the water dries off.

Allan

 

[jimmy]

It's most likely to be the auxillary drive belt tensioner or the belt itself. Multiribbed belts do get noisy as they get old and dirty. And MB's are renowned for the tensioner to become noisy. You may also want to change the shock absorber on the tensioner too.