1996 850 glt automatic, nonturbo, 112K
timing belt and serp. belt changed at 70k

i've been troubleshooting this annoying grinding/moaning sound for a good while. it seems to come from the drive/serpentine belt area and gets more intense and higher in pitch with higher rpm.

i replaced the serpentine tensioner... but this proved useless.

maybe this will sound familiar to someone:

http://www.viotti.com/mcbride/serpentine.mp3

I had my wife depress and release the pedal while i recorded the sound, hood up, focusing on the serp. belt area.

any ideas? i'm stumped. maybe a timing belt tensioner?

thanks in advance!
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1982 240 DL (265K) , 1996 850 GLT (110K)

Quick update: thanks to your help in locating the problem, I had my local shop replace the power steering pump with a new unit from FCP (Volvo OEM), and now the noise due to bad bearing (listen to posted mp3) is gone. I did wait over a week to get it, but the savings were huge: $215 from FCP compared to $575 from the dealer and the other local Volvo parts store. After changing out the serpentine tensioner (result of misdiagnosis), idler pulley (cheap to swap), psp, and serp. belt, I can feel pretty confident about the drive belt area.

By the way, when refilling the system, regular power steering fluid was used. Is this anything to worry about, or is the substance the same/similar to ATF?

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1982 240 DL (265K) , 1996 850 GLT (110K)

Well, folks, thanks to your help, I think I have isolated the terrible sound: power steering pump. I got a mechanics stethoscope and listened to the timing belt through the cover--no grinding or unusual sound there. I then listened to the alternator, AC, everything else on the drive belt. No loud noises, except from the PSP itself. FCP has PSPs new for 200 and used for 105 (made by Crown). The next step is to remove the serp belt and let the car run w/o, just to be sure (per Mark's suggestion). Will let you all know the final outcome.

Thanks!
Paul
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1982 240 DL (265K) , 1996 850 GLT (110K)

Before changing the pump think about this. If the pump's bad, chances are the fluid's contaminated with metal dust. This is now throughout the system including the rack, and will take out the new pump. I suggest hanging a small ring magnet (my local hardware has them loose) from the cap with a short wire or nylon cord to collect as much of the dust as you can before you change it. I would also install a magnafine filter in the return line for the same reason. Buy 2 and put one in now and one after changing the pump.

I would vote for Klaus' "timing belt is touching the plastic cover." While looking under my hood one day, I leaned up against the cover and it made the same sound. Just take the cover off and see if the noise is still there. If so, then you'll have to do some modifying of the cover for it to no longer touch...don't know if this means bending a clip or something more involved. While in there you may be able to pinpoint things more easily too.
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1998 S70 T5 Emarald Green Metallic, 2004 V70 2.5T Ruby Red, Previous Owner of Black '94 850 Turbo Wagon. My cars have been running so well lately they've got me worried.

I can hear the injectors clicking! The last time I heard noise like that was on a V6 with the belts on too tight.
Use a long piece of tubing or a piece of metal and move it to the center of the rotating parts and see if you can pinpoint the terrible noise. It could come from the timing belt (I hope not). Or the TB is touching the plastic cover?

Klaus
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(V♂LV♂s 1975 164, 1995 854T, 1998 V70R)

Thanks for the insights, Klaus. Maybe I'll replace the timing belt prematurely and timing tensioner as an insurance policy. Do you mean using the tubing or piece of metal to listen more accutely to the rotating parts along the serpentine belt?

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1982 240 DL (265K) , 1996 850 GLT (110K)

Yep. One end on your ear, the other end as a probe. Metal stick will have to touch the metal on the car, of course. Which means dead center on round moving parts! A tube is safer, no touching of metal parts required.

Klaus
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(V♂LV♂s 1975 164, 1995 854T, 1998 V70R)

I can definitely hear the rubbing noise but unless someone has been inside that timing belt area recently the cover is not going to start rubbing just for fun. If it was poorly installed at the last belt replacement I would think that this would've surfaced much sooner. I also hear the bad bearing noise but the pitch is not consistent with the typical tensioner or idler pulley for the timing belt.

This is what you need to do:
With the problem duplicating, take the serpentine belt off and see if it continues.
If it does continue then remove the timing belt cover and use a mechanic's stethoscope to listen to the non rotating parts of the pulleys. The stethoscope it cheap and can be bought at Harbor Freight among other places and be damned carefull with the probe around the spinning belt and pullies.

In the event that the noise goes away with the serpentine belt removed you then know what circuit it is in. Truthfully my gut says "alternator or P/S". It has the right kind of grinding noise for that. Really bitchen use of the MP3 file by the way, kuddos to you and your lovely wife.

Mark