AC Compressor Whine

[pumm3l]

This noise just started recently when the cold weather started. I have a stethoscope and I'm pretty sure I narrowed it down to the AC compressor, it's the only place that I can really hear the noise.

What would cause the AC compressor to whine? It still blows cold air, seems like it has a full charge because it's not really surging when I have it on.

[teflon_jones]

Can you describe the whine a little better? Is it tied to engine speed?

[pumm3l]

yes it gets louder when the rpms go up, the best that I can describe it is a faint supercharger like sound. I can try to get some audio with my digital camera but I don't know if it'll be good enough.

[pumm3l]

took a short clip of the noise:

http://www.stempsite.com/misc/ac_whine.wmv

[IwannaWRX]

have you checked the idler pulley? one of our cars did that and it happened to be the idler pulley and a lose belt tensor

[pumm3l]

thanks I'll check that out.

[pumm3l]

looking at this diagram, is it just the pulley that needs to be replaced or do I also need 73134 (Adjuster-idle pulley)?



Thanks again..

[DSM-2-WRX]

I'd like to know the answer to this as well (i.e., which specific parts to replace), as I'm having the exact same problem. I also used a mechanic's stethoscope and found the noise was loudest when I placed the tip on the adjuster bracket (part # 73623A in that photo) just in front of this pulley.

[SilverScooby02]

I had the exact same problem, I replaced the idler pulley and both belts. Relatively cheap and simple fix, I think I paid just under 100 for all the parts and they were replaced in an hour.

[pumm3l]

I'd like to know the answer to this as well (i.e., which specific parts to replace), as I'm having the exact same problem. I also used a mechanic's stethoscope and found the noise was loudest when I placed the tip on the adjuster bracket (part # 73623A in that photo) just in front of this pulley.

I bought the idler pulley a few weeks back. I haven't had a chance to put it on though, it's just been so damn cold and mixed with a little bit of laziness makes a bad combination.

As soon as I put it on I'll let you know if the noise goes away.

[DSM-2-WRX]

Cool. Let me know how it goes. I just replaced the clutch (the transmission clutch that is) over the weekend, so I need a break from the garage!

[pumm3l]

Cool. Let me know how it goes. I just replaced the clutch (the transmission clutch that is) over the weekend, so I need a break from the garage!

eh, so this thread got me off my ass and I finally put on the pulley today, noise is 100% gone. Took me about 15 mins to take it off and put on the new one.

Part no. from Subaru is 73131FC000 -- I paid $25 for it. Glad that's all it was a few people mentioned AC clutch which was what I was planning on doing until I came here.

[DSM-2-WRX]

Awesome, glad it worked for you!! Thanks for posting the results. I'm almost 100% positive that this is what is wrong with mine. IIRC, the bad clutch causes noise basically whenever the compressor switches on, whereas this noise occurs all the time, and is RPM dependent (and not related to the transmission). I'll post up as well after I replace mine.

Is there any reason to replace the other piece that you were asking about?

[pumm3l]

Awesome, glad it worked for you!! Thanks for posting the results. I'm almost 100% positive that this is what is wrong with mine. IIRC, the bad clutch causes noise basically whenever the compressor switches on, whereas this noise occurs all the time, and is RPM dependent (and not related to the transmission). I'll post up as well after I replace mine.

Is there any reason to replace the other piece that you were asking about?

no not as preventive maintenance anyway. All it does is attach to the pulley and then the big ass bolt pushes that piece up and down putting more/less pressure on the belt. Only if it broke would I replace it

[DSM-2-WRX]

Cool, thanks again!