What was found
THE PILOT SMELLED A BURNING ODOR IN THE CABIN ALONG WITH A HEAT/TEMPERATURE RISE. IMMEDIATELY LANDED AND NOTIFIED MX. MECHANIC FOUND THAT THE AIR CONDITIONING COMPRESSOR APPEARED TO HAVE LOST OIL RETENTION THROUGH THE DRIVE PULLEY SEAL. THE COMPRESSOR AND CLUTCH SHOWED NO OUTWARD VISIBLE DEFECTS OTHER THAN THE OIL LOSS. SUSPECT AN INTERNAL DISCREPANCY TO THE COMPRESSOR. DURING A GROUND RUN, THE COMPRESSOR WAS OBSERVED TO ENGAGE/DISENGAGE THROUGH THE CLUTCH SYSTEM ABNORMALLY CAUSING A LACK OF COOLING AIR PROVIDED TO THE CABIN. THE COMPRESSOR WAS REPLACED WITH A SERVICEABLE PART. THE DRIVE PULLEY AND BELT WAS INSPECTED, SYSTEM SERVICED AND GROUND RUN WITH NO DEFECTS NOTED. THE ACFT WAS RETURNED TO SERVICE.