A/C System - Poor Performance, or Occasional Loud Noise: Overview
Group 64Heating and
Air Conditioning
Bulletin Number
64 09 92 (3529)
Woodcliff Lake, NJ
December 1992
Product Engineering
This Service Information bulletin supersedes the orange Service Information bulletin number 64 09 92 (3529) dated June 1992. Please remove and discard Service Information bulletin number 64 09 92 (3529) dated June 1992 from your S.I. binder.
THE PROCEDURE OUTLINED IN THIS SERVICE INFORMATION BULLETIN SHOULD BE PERFORMED ON ALL AFFECTED VEHICLES THE NEXT TIME SUCH VEHICLE IS IN THE SHOP FOR MAINTENANCE OR REPAIR.
SUBJECT:
Air Conditioning Overcharged
MODELS:
E36
Situation:
Air conditioning has poor performance, or occasional loud vibrating noises perceived coming from the glovebox area. The air conditioning "high side" pressure often exceeds 300 psi.
Cause:
Several E36 vehicles have been factory fitted with a condenser which has a smaller volume, and a lower refrigerant requirement. However, some vehicles have been charged with the "typical" full amount of refrigerant. This causes excessive high side pressure, poor air conditioning performance, and increased compressor cycling. In some extreme cases, the high side pipes will intensely vibrate, both visibly and audibly, for a period of a few seconds. This vibration often occurs after a steady highway drive of at least ten minutes on an especially hot day. As the vehicle slows down to idle, the output air will turn warmish and the pipes may vibrate.