brus brother Posted January 16, 2011 Share Posted January 16, 2011 05 OB started high pitched "ringing" that goes away when the a/c is turned on. Idler?? Happens at one particular rpm only. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted January 16, 2011 Share Posted January 16, 2011 Being RPM related, can you replicate this noise with the car sitting still? Quote Link to comment Share on other sites More sharing options...
brus brother Posted January 16, 2011 Author Share Posted January 16, 2011 Yes. Car was sitting still, hence I was able to put my ear close and identify location. This would have been scary in motion! I was just monkeying around removing the piggybacked anti-fouler on the cat when I noticed the sound. It is coming from the area of the p/s a/c or idler and happens at idle and goes away when I turn the a/c on. Car is due for timing belt in 1,000 miles (maybe tomorrow) local special of $299 and I guess they'll have everything out and open anyway. Any thoughts? Quote Link to comment Share on other sites More sharing options...
94Loyale Posted January 16, 2011 Share Posted January 16, 2011 (edited) Most of the time, if the noise sounds like it's coming from the compressor and goes away when the ac clutch kicks in. It's the bearings in the compressor. I'd pull the ac belt off, then run it and see if the noise is gone completely. That way if the noise is gone, you narrow it down to the compressor or idler. Next, pull the idler and check the bearing, and spin the wheel on the compressor too, see if you can feel any roughness or noises. Edited January 16, 2011 by 94Loyale Quote Link to comment Share on other sites More sharing options...
zacyork Posted January 16, 2011 Share Posted January 16, 2011 a mechanics stethescope would work. if you dont have access to one you can use some spare smaller coolant hose. plug one ear and put the hose in the other. put it next to your pulleys. Quote Link to comment Share on other sites More sharing options...
brus brother Posted January 16, 2011 Author Share Posted January 16, 2011 Light spray of belt dressing (on the belt) seems to have stopped the noise... for now. Belts have over 6 years and 104,000 miles so I suppose they may be a bit on the dry side. As I said, timing belt being done at dealer tomorrow so I'll have them check the pulleys and supply new fan belts for re-installation. As always, thanks for all the feedback and what-if scenarios. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted January 17, 2011 Share Posted January 17, 2011 Accessory belts are supposed to be done every... 60k these days? Of course they can usually go for longer, but most of the time they start screaming after a few years. Yours has done well to still be in one piece after 6 years. I'd bank on the belt first. If that doesn't fix it then Ac compressor pulley bearing is probably going bad. Quote Link to comment Share on other sites More sharing options...
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