I am getting a loud thump from the engine compartment when I turn on the A/C after it has been off for several days. It has happened twice. It almost sounds and feels like I ran over a 1' piece of 2x4 and it hit against the wheel well. I can feel the thump in the floorboard when it happens. It this just a extra noisy clutch engagement? Because in both instances, the thump occurs AFTER I hear the clutch engage. Any ideas?

 

This is a normal characteristic of your vehicle.
Oil builds up in the compressor and when you turn the A/C on, the compressor has to push the oil out.

 

Thanks for the reply. It never did this before. I'll bet it's hard on the compressor. When the A/C quits, I'll probably just drive around with no A/C since I distrust mechanics so much. No matter where youtake it, they'll want to replace half the components and then it will just break again less than a year down the road. I've been through this before.