Ac was low on charge but blowing cool air. Then started making a rattle noise. I pulled out the tensioner pulley. It is ok. Refrigerant is leaking from Schrader valve for sure. Could low refrigerant cause the compressor to make the noise? Or is it more likely the compressor has failed?

 

last time my ac rattled the clutch fell off.. pulley or clutch has probaly failed

 

Open the hood and pinpoint the source of the noise.

 

Um, ac system would not cause a rattling noise, you got something loose.

 

"Rattle" sound comes from the compressor/clutch. Sounds like this, (this is not my case, but the sound is the same)

It only makes the sound when AC is "on".

Schrader valves are leaking, refrigerant is low.

 

Make sure the high pressure line isnt rattling against the condensor fan shroud

 

It's not the line. Compressor/clutch area unfortunately.

 

Replace the armature plate and pulley.

 

I have a similar issue, but for me a pulley or something squeals when I turn on the ac or shift from park or neutral to reverse or drive, but only when the car is hot.

 

Get it fixed before this happens.

 

Could be a loose belt. Start there.

 

Shop removed refrigerant, replaced schrader valves, placed under vacuum. Vacuum is good. Compressor is bad.

Any recommendations on make of replacement compressor?

 

Or it's just the clutch and the shop naturally gravitates toward higher profits? That's the caveat of posting self-serving shop results on car enthusiast forums. You'll never really know the truth without doing basic diagnostic tests yourself.

 

When I take it apart this weekend, I'll find out. A clutch assembly is over 1/2 the price of the full compressor. The shop evacuated the system, and replaced the schrader valves. $100. I'm pretty thrifty ;-) but that's in my tolerance range. The shop was certain the noise was hammering pump pistons vs faulty clutch. We'll know.

 

...and you believed the shop. But why?

It's possible that the shop is right about the diagnosis. It's equally possible that the shop is wrong.

My point is that charging you $100 to replace schrader valves and recharge the system with refrigerant told you absolutely nothing about whether the compressor or the clutch caused the noise. Please explain how $100 of irrelevant work convinced you that the compressor was bad and why you would trust this shop. What am I missing?

In the end, will you conclude that the compressor was actually bad after paying even more money (1) to buy a new compressor, clutch, and receiver/dryer, (2) to place system under a deep vacuum to check for leaks, and (3) to recharge system with correct weight of refrigerant? Seems like a stretch based on information you have posted here.