Suburban 3/4 Ton 4WD V8-305 5.0L (1986)
It has been reported that the desiccant (moisture absorption material) used in 1992 and older R-12 A/C systems is incompatible with R-134a and PAG
oil. The older desiccant was designed specifically for R-12 systems, but testing has shown that it is NOT necessary to replace the older desiccant just
because the vehicle is being retrofitted to R-134a. 1993 and newer GM vehicles use desiccant designed to be compatible with both R-12 and R-134a
systems.
The amount of desiccant used in most GM vehicles is designed to last for at least seven years. To help maintain adequate protection for vehicles that
must be retrofitted, it is recommended that the accumulator/dryer, which contains the desiccant, be replaced if the vehicle is more than five years old.
"O" RINGS
While continuing to service with R-12, be sure to use "O" rings and seal materials which are compatible with R-134a and PAG oil. This practice will
eliminate concern in case the vehicle requires retrofitting later in its life. All "O" rings and seal materials available from GMSPO are compatible with
R-134a systems.
RETROFITTED SYSTEM PERFORMANCE
Currently, it appears that for most GM vehicles, the retrofit procedure will require minimal changes to the existing system. Some vehicles may need
additional parts and/or procedures to provide acceptable performance and/or durability. Our testing has shown that vehicles that have undergone
recommended retrofit procedures will, in most climatic conditions, be minimally affected in terms of A/C performance.
SERVICE POLICY
Basic service policy is as follows:
During Warranty - If an R-12 produced vehicle A/C system must be repaired or recharged under warranty, repairs will be completed using R-12. If R-12
is unavailable or unaffordable, GM will notify the dealer body and will pay for the warranty repair and the retrofit to R-134a.
NOTE:
It a customer requests that an in-warranty vehicle be converted to R-134a, and the R-12 system is functioning properly, the customer will be expected
to pay for the retrofit.
Out of Warranty - The cost of the conversion will be the responsibility of the customer.
