Flushing A/C System

System flushing, using either R-11 or any other flushing material, is not approved by GM for any A/C system.


NOTE: An aftermarket filter with an integral orifice is available to protect refrigeration systems that have been contaminated, eliminating the need for system flushing. Refer to Refrigerant Filter. Refrigerant Filter

R-11, a material commonly used as an A/C system flushing solvent, has been found to be chemically incompatible with Polyalkylene Glycol (PAG) lubricant. Technicians should be aware that residual R-11 remaining in an R-12 system will be very damaging if the vehicle is retrofitted to R-134a later in its life. For many years GM has recommended the use of in-line filters as an alternative to system flushing.