Loud Air Conditioning Noise (Yes, I searched)

[Jackhill442]

My '96 country with 200K has ice cold a/c. no compaints there. The system has never been touched. But at idle on hot days, sometimes it will all of a sudden make this loud trombone like vibration sound. I can feel vibes in the line when it does this. It will go away if I rev the engine, then come back at idle. It only does it sometimes, and it doesn't affect the performance of the system, but the sound is so obnoxious and embarrasing. Any answers?

 

[Jackhill442]

forgot to add, it has been doing this for at least 3 years, and it has never gotten worse or better, and has not affected the system in any way. I have tried securing and bending the lines with little help.

 

[baronf]

you know... the compressor has to cycle in order for the ac to work. when the compressor cycles and you are at idle you can feel some slight vibes in the seat, thats normal. while its a little loud, i doubt it's "embarrasingly loud".

if your system is low on refrigerant it will cycle more frequently. get a gauge and check (low pressure side) to see if you need a little more refrigerant.

 

[Jackhill442]

no, this is not normal. You could probably hear this from 50 yards away. It sounds like some kind of mutated horn.

 

[Rocketman]

AC Clutch?? Bearings?? Is it ONLY when AC is on??

 

[gradon]

My buddies 96 does the exact same thing as OPs. Humming from the condensor block at idle and goes away with throttle(more like a muted flugelhorn, lol--I play t-bone). AC is ice cold. Any chance there is too much freon in the system?

 

[joe_peters]

Wife's 95 Windstar did the same thing. It would sound off when started cold in the morning, and then again when it cycled.

Never bothered to fix it.

 

[FallibleXJ]

My 97' XJ did this a while. It disappeared after I hosed out my engine compartment one afternoon.

 

[robert2008]

Mine was loud before replacing my serpentine belt and adjusting it to the proper tension.