08 Sierra A/c Compressor Startup Noise

saxdogg · October 27, 2008

Hey guys,

I orig. posted this in the technician section, but didn't really get any bites. Wondering if you other owners had this issue and how your dealer dealt with it...

I know of the TSB that describes a start-up noise with A/C compressor on the 07-08 GMC Sierras, etc. when the temperature outside is above 95 F. The TSB called it a "refrigerant hammering" sound if I remember it....it sounds like an air compressor in your shop to me, but only does it when the truck is cold, on an initial startup, when it's super hot outside.

Anyways, my dealer performed the TSB, which is only a software update, and it did not fix the problem. Now they want to try and reproduce it and probably just throw parts at it since they really don't have anything further to go on...it is too random for me to give it to them to let sit overnight and try once in the morning and besides, it's not warm out anymore anyways... the a/c has always worked fine, it's just annoying (and embarassing!) on a new truck.

My question is, have you techs/other owners found a solution or heard of this? What has fixed it if anything?

JP

Zembonez · October 28, 2008

My compressor makes a slight noise on initial turn on. It's a little like the rattle in an older engine on startup before it gets oil pressure. It only lasts for a second or two but I have noticed it. Mine hasn't changed since new. Is this anything like yours?

saxdogg · October 28, 2008

mmmmm...no, I would describe mine as like an air compressor, you know, like you run your air tools with or inflate a tire...it's loud and vibrates the truck a little bit....sounds much more violent than I think it really is, as the a/c has always worked great...it'll do it for only 2-3 seconds, but it seems like an eternity while it's happening. It's not the initial clunk you get sometimes from a/c compressors...most of my cars have done that at some point...

It's just embarrassing more than anything when you come out to a parking lot after it's been parked awhile, it's super hot out (like earlier this summer), and everyone stares at your truck when it does it...with that "isn't that thing brand new?" look on their face...esp. those ford jerks LOL

Like I said the TSB is in the WIKI page, but it didn't work. I didn't see how a software update would solve "refrigerant hammering" anyways...it works fine, which is why I'm hesitant to take it in and let them start tearing away at it. may wait for next summer and TSB version B.