Whenever A/C is on, there are noises around compressor. No noise at all when A/C is off.

A/C is cold and never stops.

A serpentine belt or idler pulley problem? The timing belt was changed this Feb.

After search on this forum, I think I already get the answer, right?

 

depends what kinda noise it and and stuff. but sounds as though it could be a bearing or the clutch.

 

Right, may be just before the A/C stop working......

 

a/c usually stops because there becomes a leak in the lines that lets the freeon (spelling?) out.

 

My assumption is that it is not a serpentine belt... as when A/C is off, no noise at all.

 

ya but when the a/c is off then the a/c compressor disengages (because of the clutch on the compressor. so it "could" be the belt.

is this noise a squeal, or metal on metal rotation sound, or a clank or what is it?

 

I would say the compressor has been low on oil in the system and the compressor it going bad.

 

I have no idea to describe the sound by these terms. I uploaded a video on youtube, so you can check and tell me which it is.

http://www.youtube.com/watch?v=eee3-7EhcXA

Here are what I have done: start engine, turn on A/C at 00:00:34, turn off it at 00:00:46, turn it on again at 00:00:50, turn it off at 00:01:04, race the engine at 01:00:07. You can hear the noise caused by turning on A/C.

 

Is that metal on metal rotation sound?

 

The compressor is bad. Sounds like it did not have enough out and went bad.

 

Well, it still blow out pretty cold air. I am in Dallas and feel good with that.

 

Yes but one day it will stop.

 

Just purchased one used compressor for $40 on ebay in case. I am not sure what other parts I should also prepare, but drier, o-rings.

 

add a can of compressor oil and let it go untill it gives up- that might still be few years from now.

 

Any easy way to add it?

I found it not easy as i thought.

http://www.ehow.com/how_4762765_add-oil-ac-compressor.html

 

Thats a much longer route. What I do is get a can of 'Redtek' oilcharge from partsource and connect it to the adapter kit and connect the kit to lowpressure side port. Start the car with airconditioning on and just empty the can into the system following simple instructions.

Cost= Less then $15 and total time is less then 10 minutes.
Following links might give you some information and wath the video in first link:

http://www.redtek.com/products_refr.html#
http://www.redtek.com/win_oilcharge_prod.html

 

nice!

 

I have been to Autozone this morning, and they have PAG recharge kit.

For Volvo 850, which viscosity is best? I think 100 is OK.

 

Honestly, I never bothered about the viscosity figure and just always get 'OILCHARGE' can as in the link above and it works without any issues.

 

I add on can (8oz) compressor oil in and the noise seems decrease a little bit. Still feel trembling compressor when it is on, especially when accelerating.

Anyway, blowing cold air is good enough now.