Clunking/banging heard and felt when car is hot and A/C on

Just picked up a 97 740il with a little over 105k miles on it. For the last couple weeks, it's been running perfectly. Got the oil changed to new synthetics, new coolant put in, and also new brake fluid.

Today after driving a few local miles in about 90+ degree moderate humid heat, a bad clunking or banging started from the front end of the car. Sort of felt like something came loose and was bumping around and ready to fall off. Stopped and checked for broken mounts or loose parts, but didn't find any. After the car cooled down after 2 hours, I tried driving it again and didn't feel anything again.

But 1/2 hour later, after driving about 3 miles w/ the A/C on again, the problem started again. Wonder if it might be the A/C causing something to loosen up, something that reached a high-temp and go screwy (transmission?), or an exhaust catalytic converter problem. I did notice a rattling cat...one was replaced by the previous owner at one point he said...so it looked like the other one is going also. But a rattling cat shouldn't cause a bad clunking and banging problem, felt within the car...?

Any ideas? Thanks.

Sounds like an a/c compressor problem. See if you can tell if the noise is coming from the compressor itself.