Bad Compressor Or Something Else?

[ashleyrihner]

I have a 2001 Chevy Tahow (2WD). I am hearing a rattling noise under the passenger side of the hood. The noise is apparent only when the A/C is on and occurs when I hit b/w 20-30 mph. The sound is not noticeable in the early hours of the day. However, once the temperature rises, the sound returns but it is inconsistent. Assessments provided by others so far:

 

1) a bad expansion valve

 

2) Need a new compressor

 

3) Clutch trying to lock up in the compressor

 

 

 

I have read that there may have been a service letter sent to customers regarding the clutch scenario. Does anyone know if such a letter or known problem exists? What exactly does a faulty compressor sound like? I'd appreciate any input!

[Zembonez]

I have read that there may have been a service letter sent to customers regarding the clutch scenario. Does anyone know if such a letter or known problem exists? What exactly does a faulty compressor sound like? I'd appreciate any input!

 

Any new noise from underhood is not good. It is possible that the compressor is making noise or it could be something simpler like an idler pulley going bad. From your description that sounds like a likely candidate. I would suggest having somebody look at it before "IT" decides to lock up and possibly do more damage to the system or eat up your serpentine belt... Nothing like being stranded on a hot day.

 

As with most mechanical ailments, it's not recommended to wait for it to fail completely before having it looked at.

[mooreapi]

NOLA,

Most likely it is the idler pulley bearing. Does it sound like a rattling heat shield sort-of sound?

I had one (idler pulley bearing) go bad. It threw a belt and thought the compressor had seized. Replaced compressor, threw new belt and when I looked the idler bearing was falling apart. Replaced tensioner/idler pulley and it's worked ever since.

 

I also noticed that my A/C compressor gets a little noisy when I'm low on freon (small leak somewhere), but when I add more, especially if it has oil, it quiets down a lot.

 

Remember, idler is cheaper to replace than compressor, and if you're going to replace the compressor (with high miles) you should also replace the idler (ask me how I know!)

 

Matt

[atboley]

on those engines, there is a seperate belt and tensioner for the a/c compressor, so the

problem i doubt is the pulley or the idler... what you can do is put it in park and turn the a/c on rev it up to around 4000

rpm and hold it there(make sure the compresser comes on while your doing this), if you here the sound and then it goes away right away when you turn the a/c off, you have a compressor thats locking up and will eventually seize...

you need to replace the compressor and while your at it the compressor may have circulated metal thru the system

so you should replace the orifice tube also...

[alvocado]

My compressor was failing a few weeks ago and it was easily diagnosed by switching on the A/C and revving to about 1500 RPM. You could hear it rattle and hammer. The issue went away completely when the A/C was off. You need to replace the accumlator and orifice tube if the compressor needs replaced.

 

If you find that's the issue, look at buying a replacement from Rockauto.com. I bought an exact Denso replacement for half of what the dealer was charging. Search for a thread I posted a few days ago with a 5% discount code.