Started my 2001 XL7 4X4 6 cyl. this am to warm it up. After about five minutes, the belt that drives the pwr steering and ac compressor started to squeal and smoke. Turned off the defrost and the ac shut down and the noise stopped.

I haven't started troubleshooting yet, but it sounds to me like a bad compressor.

Anyone out there have experience with these? Are they rotary or piston, can they be rebuilt or not, and any tips or suggestions before I start. I am a universal certified refergerant tech. and have access to the equipment.

Thanx
GilT

yup that AC clutch froze up ...

Time to convert to on-board air compressor!

More likely the AC compressor itself locked up rather than the clutch locked since the problem went away when you disengaged the electric clutch by turning off the A/C.   Either way, it's time for a new (or remanufactured) one.

Occasionally, there are remanufactured units that appear on ebay that go for very reasonable prices.

I ended up buying a used one for my '93 4dr 'Kick because I didn't have money at the time a remanufactured one appeared on auction...

God luck!  

Time to convert to on-board air compressor!

That's what I did when my AC compressor siezed.  I bought a new compressor on E-bay, and converted it to an air compressor.  No regrets.

- Craig