INFO BULLETIN: USE OF R4 COMPRESSOR SHAFT NUT ELIMINATE

SUBJECT: COMPRESSOR SHAFT NUT ELIMINATED

MODEL/YEARS: ALL WITH R4 OR HR6HE COMPRESSOR

Effective after July 13, 1992 for the R4 compressor or April 28, 1991 for the HR6HE compressor, the shaft nuts were/are no longer produced for these units. This affects both production and service compressors. The elimination of this nut has been made possible by improvements in the clutch driver to compressor shaft press fit. If you receive an air conditioned vehicle with an R4 or a HR6HE compressor and there is no compressor shaft nut present, no attempt should be made to install a nut.

If it is necessary to turn the compressor shaft for leak testing, a 3/8 x 24 (for the R4) or M9 x 1.25 (for HR6HE) threaded nut may be installed on the shaft to facilitate turning the shaft with a wrench.

The compressor build date can be determined by the six digit code number on the compressor tag. The first two digits denote the month, the third and fourth digits the day, the fifth digit the year and the last digit the shift number. As an example, compressor number 071321 was built on July 13th, 1992 on the first shift.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.