Thanks in advance, everyone. I was driving my '97 965 (168k) home from my son's baseball game (100+ degrees in TX) when I started feeling a vibration through the steering wheel - it felt like it was engine accessory related. I switched the a/c compressor off and the vibration went away.

I pulled over and popped the hood, turning the a/c compressor off and on. The vibration would begin when the compressor clutch engages. There is NO noise. Also, the a/c performance seems to be way down all of a sudden.

What do you think before I R&R the compressor? They seem pretty reasonable online ($250 with clutch for remanufactured units and $350 for OEM new -- will research this more). But don't want to order the whole ball of wax if it's not necessary at this point. Thanks!

http://www.discountacparts.com/addtocart~year~1997~make~Volvo~model~960~descript~A-C_Compressor~part~60-01481.asp

When the unit is engaged, is it also cycling quickly? or is it just running constantly (with diminished performance and vibration?

If the compressor is vibrating badly you will likely need to flush the entire system as well to get any particles out of the system (evaporator and condenser) otherwise you run the very real risk of ruining your new compressor. You will also want to replace the dryer and the orifice valve.

DEWFPO
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1998 S90 086,388 and 1995 964 154,100

Thanks, DEWFPRO. It doesn't seem to by cycling quickly, but I'll check again.

Great points on the dryer/oriface tube. This could be an expensive fix...nearly 1/4 of what my jewel 965 is worth, I'm afraid.

Tell me, would the vibration/diminished performance be the sign of a compressor or clutch going south? Thinking the compressor but just wanted to verify.

Hi Chris,

In my experience if the clutch is going, it either doesn't engage at all or it makes a lot of noise. Chattering if it's slipping or an ear piercing squealing sound if the clutch bearing is dry.

If the performance has dropped it means you've either loss the proper charge of refrigerant or your compressor is not compressing it.

I have a had a recurring problem with the unit on my 98 S90 blowing off refrigerant (high pressure relief valve tripping) on really hot days when the pressure exceeds the relief valves 538 psi tripping point. When this happens you will hear a loud, jet engine type of roar coming from the engine compartment for about 5-10 seconds and you will sometimes see white vapor coming from under the hood (if you are stopped at a traffic light). You won't see the vapor if the vehicle is moving. After this happens there is greatly diminished cooling but no unusual vibrations. Recharging the system brings back the cooling capacity.

You could....... try to recharge the system and see what happens. I doubt you can make things much worse by doing this if the compressor is already seriously damaged. You might get lucky for the cost of a R134a can. If it doesn't work, you know you are in for a system overhaul.

Good luck.

DEWFPO
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1998 S90 083,228 and 1995 964 154,100

Thanks, DEWPRO. I agree with your experience about the clutch...same as mine. I also spoke with a good friend of mine who suggested a few things to check/try.

I plan on testing things tonight when I get home from work. I want to remove the skiplate and get a good look/listen to see what is going on at the compressor area, I want to see how much she's cooling or not - and check the accumulator. And I've got freon to add if necessary. Your advice about adding another can is good, especially if my vibration goes away on the cold engine (with the a/c on).

I'll report back asap and let you guys know what I find. And thanks for your advice, DEWPRO. BTW, I've never experienced the "blowing off" you have. Wild.

ALSO, I vastly overestimated the cost to completely R&R the underhood components. I can do it all (minus freon) - including the compressor (reman), accumulator and oriface tube and seals for under $250. Worth a shot for sure. Hopefully it won't come to that.

I've got a Zexel compressor #9447842. I believe these are replaced (per the FCP groton site to #8601531).

I put a can of R134 in and while she got a little cooler, the vibration still persists. There is no excessive cycling of the compressor or clutch noise. And no oil or leaks from the clutch or compressor area. I put a long-handled screw driver to the compressor and my ear with the clutch engaged and not engaged, and there was no real change in tone or pitch. She is not excessively noisy.

What do you think? Replace the compressor/clutch, accumulator and oriface tube, clean out the system, and let her rip? Also, reman or OEM?

OEM - $340 shipped from FCP / e-bay (#8601531)
Reman? - $250 or so shipped which would include the accumulator, oriface tube, seal kit and oil from (http://www.acpartshouse.com/showitem.aspx?id=100774)

All these places require a certified a/c repairman to do the work or the warranty is void. As I'll do this myself (trying to keep the costs way down on this), it may not make sense to buy the OEM.

Any further advice would be awesome. Thanks!

You mentioned that the noise is no different with the clutch engaged or disengaged, how about the vibration? Does it vary with clutch engagement?

I agree with Toms90. I would remove the serpentine belt and try to rotate the clutch on the compress and see if you can feel any roughness or noise. Does it freewheel easily, quietly and without wobble or play.

DEWFPO
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1998 S90 083,228 and 1995 964 154,100

1) Take the belt off, and wiggle the ac clutch by hand, with ac off and ac on for loosness ( along with other near by puleys )

2) Check for any missing bolts / cracked moutnings / brackets/ on the compressor?

3) I just replaced the ac clutch on my s90, so trust me, it was a PIA to remove the compressor.

Tom