My best guess here is that the ac clutch is going or has gone, hence the grinding noises and the belts getting loose. It may be the compressor, but Im thinking if the compressor was gone then the thing would either seize or youd have looseness and such all the time....either way thats the area to start searching. If nothing blows....Im presuming no air flow here thru the ducts....does the car have any of the ATC systems? Im no expert on them but I think the FSM will lead you thru that, as in some cases the fan may not blow at all unless other parameters are met. Id defer to the guys with ATC on this , or the guys with the 72's. The thermostat should still be on top of the water pump housing....it probably has an angled housing to get the upper hose to clear the ac compressor. Follow the upper hose from the radiator back towards the engine....at the engine end of the hose you should find the thermostat. Be aware, the stat itself shouldnt have anything to do with having ac or not. IF the compressor turns, has enough freon onboard and can develop pressure, and the sytem is intact then youll have to find out why the fan blower isnt working and go from there. It may end up being a case of isolate and identify the separate problems and then try and tie it together. Mikey 62 Crown Coupe