socalclimber

2002 A6 4.2 73,000 miles

I'm starting to hear A/C compressor noise (whining sound) when A/C is on, esp. around 1200-1800 RPM. New accessory belt w/ TB job, and new idler pulley. Sound goes away when I hit ECON button. It's not terribly loud, but it's a new sound.

I suspect compressor is going out. A/C is still functioning fine, but I'm concerned about the noise and potential damage if/when it gets worse. Don't let it get worse, right?

It's the Denso brand. AutoHausAZ has it for about $400 (OE Rebuilt). I will have an A/C shop install and charge.

Are the Denso compressors a weak point with Audis? Recommendations? Experiences? If noisy, is damage already done?

4Driver4

Compressor failures are very rare. Are you sure it isn't a radiator fan?

Airbag

although these can go bad in any car as pointed out is quite rare. This is the one area I would let it die before fixing it . I don't think you are gonna do any more damage as tou may find out it is not the issue..

audik0

New to Audi's 4Driver4, but are these fans suppose to be that loud with the A/C On? Mine sounds like a Jet...

2k C5 2.8L

socalclimber

I am hoping it is NOT the compressor!

When A/C is on, I don't hear the sound at idle, but when I bring the RPMs up in the range of 1200-1800, there are RPM points where it is loudest. It is engine-speed dependent, so I don't think it is any of the electric fans, but I will check more.

I put in a new accessory idler pulley (bearing made that dry, whirring sound when spun by hand) when I did TB, so I thought maybe the new idler pulley was bad. So, I changed back to old idler pulley with no change in sound (sound is still there).

I need to put my ear right there by compressor and have someone vary the RPM to confirm.

Thanks for your input!

2.7Lturbo

its the fan. did my belt and dorked up the fan clutch assembly and now it revs with the engine and sounds like a turbine

socalclimber

Ok, thanks 2.7, I'll check that. I did clean the fan clutch of oily residue with compressed air when it was off for TB, maybe I screwed it up by doing that?

I could just take off fan with clutch and see if sound goes away?

But, maybe not the clutch, as sound is not there with ECON pushed in.

2.7Lturbo

dunno man worth a try, id love to find a way to stop mine from making the noise as well.

4Driver4

Not saying it's normal, jus sayin that you want to make sure you are identifying the right source. ;-)

socalclimber

Ok, I'll troubleshoot some more to isolate noise, maybe record and post some sound bytes if I can. Thanks for keeping me on the path, Audi brothers!