A/C Continuous Loud Noise

DonW

DonW

New Member
Joined
Apr 5, 2021
Messages
22
Location
Portland, OR
My TJ has developed a VERY loud noise when the A/C is on. Coming from the engine bay. Sounds like a fog horn, definitely not high pitched whine or metal on metal sound. More of a lower frequency. I checked the horn, it's that loud, but that's not it. It's been hot, 90's, so the A/C has been on a lot. Sound is present when idling, rolling, anytime. With the A/C off, quiet and she runs just fine.

Any thoughts?

Thanks in advance, I really appreciate the feedback I've received from this site.
 
That or it's over filled (or there's a blockage). There is a pressure relief valve on the back of the compressor that sounds pretty wicked when it does it's thing. Was the system recently filled?
 
Pull your belt and see if the noise stops. Feel out the pulley on the AC compressor too.

I tried ordering just a clutch for my compressor...and failed. They have them for the newer model compressors but my 97 had a superceded part. Let me know if you need me to dig up part numbers.

-Mac
 
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Thanks for the feedback. I went out and checked this morning. The noise is gone, no idea why. I checked the compressor pulley is turning and the engine RPM changes when the A/C is on so there is a load and I assume the A/C clutch is engaging. Without the loud noise I let it run for a while and now there is no cold air coming into the cab. The hoses to the accumulator are warm.
Could the noise have been a large discharge of the refrigerant gas under high pressure? I checked the hoses best I could and no obvious splits or disconnects. Looks like it's off to the shop for an estimate. Until then, I'll just keep the A/C off and pop off the top!
Thanks again.
Also, the system has not been charged since I've owned it for the last two years.
 
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