Community Forums

surfride · 08-21-2007, 02:38 PM

I have an 05 and am wondering if this is normal, or a predictor of a problem... The AC compressor runs well, although when the transmission downshifts, and returns to overdrive, the ac compressor makes allot of noise, growling. This will continue until I cycle the power switch for the ac. Its a bit loud, but doesn't seem to effect the cooling. Is this considered normal or do I have a bad compressor?

surfride · 08-21-2007, 02:38 PM

I have an 05 and am wondering if this is normal, or a predictor of a problem... The AC compressor runs well, although when the transmission downshifts, and returns to overdrive, the ac compressor makes allot of noise, growling. This will continue until I cycle the power switch for the ac. Its a bit loud, but doesn't seem to effect the cooling. Is this considered normal or do I have a bad compressor?

kuldaddy · 08-21-2007, 02:47 PM

We had this happening, basically when the engine shifted to the next gear (usually one of the overdrive gears, we have 6 speed Allison) the compressor was making a racing noise. Took into the Workhorse service center and they changed the compressor (warranty).

wilanddij · 08-21-2007, 04:04 PM

Have your WH service center replace the AC compressor. That's what fixed the grinding noise during acceleration with our coach.

surfride · 09-07-2007, 10:53 AM

Word from my mech is WH considers compressor chatter normal. Something about the clutch slipping as the rpms change so as not to freeze the compressor. He said a new compressor would likely do the same thing.

davebuck · 09-09-2007, 02:35 PM

Mine made the same noise, took it in and the dealer replaced the A/C clutch. Nice and quiet now

wilanddij · 09-09-2007, 04:30 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Word from my mech is WH considers compressor chatter normal. </div></BLOCKQUOTE>
Get another opinion. Mine started growling during acceleration and would quit when I shut off the AC. Eventually, it started making the same noise on deceleration. A new compressor put on by Redlands Truck totally fixed the problem.

bandcworkhorse · 09-10-2007, 11:44 AM

Had my unit in last month for an obvious A/C clutch problem. (metal-to-metal screech whenever compressor clutch disengaged.) WCC elected to replace compressor. The loud "buzzing" noise we had, usually after downshifts and always eliminated by turning A/C switch off for a few seconds initially went away completely but is starting to reappear now that we have a few hundred miles on the new compressor. I don't know much about compressor design (Roots type? Vane? piston-and-plate?) but could it be that the GM supplied compressor is underengineered for a motorhome application? Does varying compressor load cause that huge mono-belt to vibrate/slip? Do 8.1L dump trucks, delivery vans, busses, etc. have the same symptoms/history?
Instrument panels and A/C compressors...things that keep the WCC warranty folks and engineers from getting a good nights sleep.

bullydogs1 · 09-11-2007, 08:31 AM

Chalk me up to one that had the workhorse problem with the compressor...workhorse center replaced compressor but then knocked off an evaporator solenoid--causing a pop sound....this compressor clutch is apparently a big thing with workhorse....