A/C startup clunk

[Sir Dan]

I have an intermittent clunk on startup of engine when the a/c compressor kicks on. Not often, but when it happens it's a bit scary sounding. I know of the TSB for a/c clunk on 07-08 trucks that involves a re-flash of the computer, but also hear that it doesn't help anyways. Anyone have any further compressor trouble or solutions with this? If it's just the noise I can live w/ it, but by the sound it makes it seems like somethings gotta give...

[waumo1]

Are you sure it is the compressor and not a blend door in the dash? Multiple GMs I've owned all developed the blend door clunk after a few years. This included a 98 K1500, 94 Buick and 02 Yukon. Sounds like somebody thumping the firewall with a mallet.

[elite0259]

My AC clunks too, always has. I'm not worried about it, I figure it might be because it's getting old