could be this maybe
SPECIAL SERVICE MESSAGES
15697 NORMAL CONDITION: MOMENTARY GRUNTING SOUND
SOME VEHICLES WITH AIR CONDITIONING UTILIZING R-134A MAY EXHIBIT A MOMENTARY GRUNT/POP AFTER BEING PARKED FOR SOME TIME & THE COMPRESSOR IS ENGAGED BEFORE THE ENGINE COMPARTMENT HAS WARMED UP. THIS IS DUE TO LIQUID R134A BEING PUMPED OUT OF THE COMPRESSOR. R134A WILL TRAVEL TO THE COOLEST POINT (THE COMPRESSOR) ONCE THE ENGINE HAS COOLED, DUE TO THE DIFFERENCE IN TEMP BETWEEN THE ENGINE COMPARTMENT & THE VEHICLE INTERIOR. WHILE MANY VEHICLES HAVE PCM STRATEGIES THAT ADDRESS THIS BY REPEATEDLY CYCLING THE COMPRESSOR ON START- UP, THIS MAY NOT TOTALLY ELIMINATE IT. REPLACING A/C COMPONENTS WILL NOT ELIMINATE THIS. COMPONENT DURABILITY IS NOT AFFECTED. MINIMIZE THE NOISE BY TURNING THE A/C SYSTEM TO VENT BEFORE EXITING, & IN MILD AMBIENT TEMPS (APPROX. 50-75F) WAITING A FEW MINUTES BEFORE TURNING ON THE A/C OR DEFROST.
EFFECTIVE DATE: 03/06/2002
SPECIAL SERVICE MESSAGES
15697 NORMAL CONDITION: MOMENTARY GRUNTING SOUND
SOME VEHICLES WITH AIR CONDITIONING UTILIZING R-134A MAY EXHIBIT A MOMENTARY GRUNT/POP AFTER BEING PARKED FOR SOME TIME & THE COMPRESSOR IS ENGAGED BEFORE THE ENGINE COMPARTMENT HAS WARMED UP. THIS IS DUE TO LIQUID R134A BEING PUMPED OUT OF THE COMPRESSOR. R134A WILL TRAVEL TO THE COOLEST POINT (THE COMPRESSOR) ONCE THE ENGINE HAS COOLED, DUE TO THE DIFFERENCE IN TEMP BETWEEN THE ENGINE COMPARTMENT & THE VEHICLE INTERIOR. WHILE MANY VEHICLES HAVE PCM STRATEGIES THAT ADDRESS THIS BY REPEATEDLY CYCLING THE COMPRESSOR ON START- UP, THIS MAY NOT TOTALLY ELIMINATE IT. REPLACING A/C COMPONENTS WILL NOT ELIMINATE THIS. COMPONENT DURABILITY IS NOT AFFECTED. MINIMIZE THE NOISE BY TURNING THE A/C SYSTEM TO VENT BEFORE EXITING, & IN MILD AMBIENT TEMPS (APPROX. 50-75F) WAITING A FEW MINUTES BEFORE TURNING ON THE A/C OR DEFROST.
EFFECTIVE DATE: 03/06/2002