190e A/c

yesterday my A/C gave me trouble, for the first time. It was working perfectly, when it suddenly switched off (going at 70mph). If I switch off the ignition and start again, the A/C does come on, but only for a few seconds. Then I can hear a loud grinding noise from the front, the engine rpm drops a lot, then the A/C switches off. This happened a few times, then I stopped trying - didn't want to damage anything else. The car is otherwise fine - just had the 30,000 mile service done.

what could it be - how expensive. Car is 85 190E 2.3 (132K), so I am not going to spend much more money on it. I live in Cleveland anyway, so can do without an A/C.

thanks.