I searched a little bit on the subject but didn't find much.

My problem: I bought a 1990 4runner that I knew the a/c didn't work on. The PO gave me a few cans of r12 to have it recharged. After spending a couple weeks finding someone to do this, I finally found someone. They put two of the cans in and my a/c worked great! 4-5 days later it quits on me. When I push the a/c button, there's a weird sound under the hood. I'm thinking it's the compressor. What do y'all think?

 

a/c compressor may be bad but,if the a/c amplifier unit is working ok if something is bad in the a/c system it simply wont engage,low refrigerant ,low or high pressure sensors,well anything.a grinding noise can tell theres a bearing or internal part broken,also check the a/c belt tensioner bearing is not locked.and get a good a/c technician if the low and high pressure ports are original tell the tech to take the time and change the fittings seals too.
good luck.

 

A bearing sounds right. I guess I need to find a good technician.

 

"grinding" might also be a bad compressor clutch. If the lining wears out OR its over charged it will make a weird noise because it cant turn the compressor.