Retrofitting Overview

A. Refrigerant and Oil Charges

^ Oil and refrigerant charge amounts are different after the R-12 system has been retrofitted to R134a. Refrigerant charge amounts are less, while oil charge amounts are greater, compared to R-12 system requirements.*

B. System Performance

^ A slight decrease in system performance may be noticed on some vehicles under certain operating conditions.

C. Refrigerant Pressures

^ R134a high side pressures are greater than that of R-12 above ambient temperatures of 68°F

D. Flushing Requirements

^ There is no need to remove or flush R-12 mineral oil from the system. Simply charge the system with the specified type and amount* of PAG oil to provide proper lubrication.

E. Use of Sight Glass








^ Mineral based R-12 oil remains and circulates in the A/C system and does not dissolve in R134a refrigerant. This results in a cloudy appearance at the sight glass making it impossible to judge the refrigerant charge amount by using the sight glass method. To prevent misdiagnosis on retrofit vehicles, apply black paint to the sight glass on block- joint (FF) type receiver/dryers. Union-nut joint (BAG) type retrofit receiver/dryers are manufactured without a sight glass.

*NOTE:
Refer to the OIL TYPE and CHARGE columns in Application Tables for proper amounts of ND-Oil 8 or ND-Oil 9.