AC in 93 Corolla

Noises are difficult to diagnose without hearing them first hand.

I doubt if the compressor magnetic clutch is the source of the noise because it probably would have to be slipping to make noise, and if it were slipping, the RPM sensor would detect the slippage and disengage the clutch and the AC light would start to flash.

It is possible the clutch, pulley, or internal bearings are making noise. The clutch and pulley can be replaced, but it is not a do-it-yourself job.

Another possibility is that there is moisture in the system, causing the expansion valve to freeze, which plays havoc with internal pressures, which puts a strain on the compressor, which might make noise.

Your best bet is to have a competent technician install a set of gauges and evaluate the performance of the system and listen to the source of the noise.

Sure, the clutch bearing only rotates when the compressor is OFF. Therefore, it won't make noise when the compressor is ON. And as Ray said, if the clutch is slipping because of excessive gap, then the difference between the engine and compressor RPMs will cause the AC light to blink and tell you the problem.

In an older system, typically the slow leak over the years deprived the compressor of lubricant, and you hear a knocking or rattling type sound. If not resolved the compressor may seize and you'll hear loud belt squeal and then the blinking AC light. Pszemol in these groups had this problem with his Camry and the dealer just tightened the belt more!

Ask your friends for a reference to a good local AC sh> 93 7AFE:

Before replacing the clutch you measure the gap. If gap is in spec it shouldn't slip.

Maybe you're just low > Can the clutches and solenoids be replaced without the expense of the

Did you check

A good mechanic can properly diagnose your problem quickly, and the most expensive good mechanic always costs less than the cheapest bad mechanic.

I'm no expert, but wouldn't a clutch problem result in chattering or squealing, rather than rattling or groaning?

Yes, and a flashing AC light and inoperative AC would also accompany the noise.