My old compressor was done for so I went to a pick n pull and got another one. Installed it along with a new belt. I also replaced the drier. Then I took it to a shop to have it evacuated, vacuumed, and recharged. Got it back, AC blows ice cold! Only problem is, when you give it gas the compressor makes a whining sound (like a remote controlled RC car lol). When you're sitting at idle, it barely does it, but the more you give it gas, the louder it gets. I thought that maybe since I didn't oil the compressor before I put it on, that maybe that was the cause. So I added oil directly into the low side (6oz PAG-46) and it's still whining. Anyone have any clues? Did I just grab a bad compressor? The AC is blowing nice and cold, the only problem is the sound.

 

Noises are tough to diagnose over the web.

I would try spraying WD40 behind the compressor pulley (between the compressor and the body of the compressor). If the noise goes away, then it is likely the bearing inside the pulley.

It could also be the tension on the belt.

 

I thought that the tension one the belt was good, but maybe I'll try loosening it a little. I will try the WD40 and see what happens. I'll also try and get a video tomorrow of the sound.

 

general rule for belt tension: on the longest straight portion you should only be able to twist it 90 degrees. any more and its too loose, any less and it's too tight

 

I actually noticed a pattern today. The noise is only noticeable when the clutch is engaged. When the clutch stops spinning, the sound stops. I also tried the WD-40 with no results!

 

Well the belt was definitely tensioned right. I tried loosening it a little which made it squeal, so I put it back how it was. doctorbee, how do I check the resistance of the clutch? I don't have a voltmeter...

 

A slightly overcharged system may whine. This is because of high load on the compressor. You need to have system pressures checked unless it was charged by weight.

On the other hand, I've had compressors that whined for a long time w/ no apparent ill effects. Whining came from an Acura 2.5TL (5 -cylinder engine) and whine remained after compressor was replaced thinking a failure was imminent.

Adding 6 oz of oil is a lot unless none was added at any time during your repairs. However systems seem to tolerate additional oil OK. I installed 8 oz when I rebuilt my AC a few years back and it's worked fine.

Make sure the whining is not the PS pump or water pump.

good luck

 

It's definitely the compressor whining. When I added oil, the pressure was at about 45. Isn't that normal? It was in the middle of the green area of the gauge. Water pump was replaced less than a month ago, and power steering pump isn't making the noise. When I installed the compressor I forgot to oil it, so I doubt if there was any in there at all.

 

High side pressure is the pressure that would cause whining. If you're getting good cooling, low side pressure should be lower than 45 psi while compressor is engaged.

good luck

 

Don't want to be the bearer of bad news but the same thing happened to me when I replace my compressor. The noise is probably because of the oil. My AC was ice cold for about 2 months before the new compressor blew. My compressor was filled with oil but you need to turn the clutch several time to lubricate it BEFORE installing the compressor. I learned this the hard way, my mechanic checked to make sure the compressor had oil (good) but he didn't rotate the clutch (bad) so the oil never got to it. I wish you all the best hopefully they will honor the warranty.