Air conditioner fan noise when driving in slow traffic

[KTYSTR]

With the gas 8.1L gas engine on W22 chassis, I assume all owners are used to hearing the two cooling fans come on at various times and make some, or very little and then decreasing noise as they cycle from on to off.
I have an additional noise that I only hear when driving in slow moving traffic with the air conditioner running.
The fan sound comes on but is screamingly loud (very loud and high pitched, high speed sound). When I stop at a stop light or in stop and go traffic, the fans sound like they will rip themselves off the coach, and then will suddenly stop and all is quiet. As I move again, the cycle will repeat.
I can instantly stop the noise by cycling the air conditioner to off.
Is there another set of fans used by the air conditioner I cannot see? Or is there only the two fans that run to cool the transmission, engine coolant and air conditioning that are making the horribly loud sound when running my air conditioning in traffic?
Anybody else had this annoying and very lound fan noise with the air on and in stop and go traffic? By the way, the excessivlely lound fan noise is never heard while driving at highway speeds...only in stop and go traffic resulting in frequent stops. I'm worried about something beginning to self-destruct. Any others out there had this issue?

[KTYSTR]

With the gas 8.1L gas engine on W22 chassis, I assume all owners are used to hearing the two cooling fans come on at various times and make some, or very little and then decreasing noise as they cycle from on to off.
I have an additional noise that I only hear when driving in slow moving traffic with the air conditioner running.
The fan sound comes on but is screamingly loud (very loud and high pitched, high speed sound). When I stop at a stop light or in stop and go traffic, the fans sound like they will rip themselves off the coach, and then will suddenly stop and all is quiet. As I move again, the cycle will repeat.
I can instantly stop the noise by cycling the air conditioner to off.
Is there another set of fans used by the air conditioner I cannot see? Or is there only the two fans that run to cool the transmission, engine coolant and air conditioning that are making the horribly loud sound when running my air conditioning in traffic?
Anybody else had this annoying and very lound fan noise with the air on and in stop and go traffic? By the way, the excessivlely lound fan noise is never heard while driving at highway speeds...only in stop and go traffic resulting in frequent stops. I'm worried about something beginning to self-destruct. Any others out there had this issue?

[Clay L]

I can't really hear the AC fans when they come on but I know they run quite a bit because I can see them through the grill.

The main fan for the engine can be heard when it comes on though. It almost sounds like I have dropped down a gear.

Going slow and having the AC on may produce enough heat to cause it to come on.

If that's not what you are hearing, then you might have an AC fan bearing going out.

[wilanddij]

Check out the "Whining While Accellerating" thread. Lots of bad AC compressor clutch going around lately.

[Myron]

I would definitely suspect the ac compressor. I just had mine replaced. The telling factor was turning the ac off and in a couple of seconds the whine would go away. It got progressively worse.

[edgray]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I can instantly stop the noise by cycling the air conditioner to off. </div></BLOCKQUOTE>
I agree with Myron, and others. Your compressor and/or compressor clutch is probably the source of the loud noise. Interestingly, when MINE started going bad, the noise went away when the A/C was turned ON-but it screamed like a banshee when turned off. Good luck with yours! ED