A/C - Cold Output Low, Compressor Cycles Off Too Early
GROUP 64Heating and Air Conditioning
Bulletin Number
64 04 87 (1545)
Montvale, NJ
January 1988
Technical Dept.
SUBJECT:
Air Conditioner Output
MODELS:
M5 (E28) and M6 (E24) with S38 engine (produced prior to 3/87).
Complaint:
Cold air output is low, and compressor cycles off too early, or may remain off.
Cause:
Heat from the exhaust manifold is directed toward the compressor temperature switch. In extreme operation conditions this can result in premature cutout of the compressor and it could remain in this mode while the heat condition persists.
Remedy:
Beginning about 3/87 in production, a special heat shield (P/N 64 50 1 385 073) has been installed between the compressor and the exhaust manifold. Cars produced prior to 3/87 should first be checked for the presence of the heat shield. If it is missing it should be installed before any further diagnosis is performed. If the shield is present, proceed to troubleshoot as per the repair manual and appropriate S.I.'s.
Installation Instructions:
Remove any protective cover, if applicable (E 28 only). Then:
- loosen the lower bolt of the compressor bracket.
- remove the forward most bolt on the exhaust manifold heat deflector 1.
- install the heat shield 2 over the loose bolt and align with the bolt hole on the heat deflector.
- reinstall the deflector bolt and tighten (43-48 N-m/31-35 ft.lbs.).
Warranty Status:
Vehicles which do not have the special heat shield installed may be repaired under the terms of the BMW New Car Limited Warranty of 3 Years/36,000 Miles.
Defect code:
64 52 05 83 00
Labor operation:
00 50 613
Labor allowance:
2 FRU