Recharging the air conditioning system in your 1999 Chevy Malibu after making repairs to the system is a two-part process. Since the system has been opened, moisture and air that has been introduced to the system must be removed. After you have removed the air and moisture, new refrigerant (the Malibu uses R-134A refrigerant) can be added to restore the system to factory performance. Some special tools and equipment are required for this service; you can purchase or rent them from your favorite auto parts store.
Separate the lower air filter housing from the upper housing by using a screwdriver to remove the screws that attach the upper housing to the lower housing. Remove the 10mm bolts that attach the lower housing to the driver-side inner fender well in the engine compartment. Lay the lower housing aside.
Locate the service ports on the air conditioning lines located under the air filter housing. Attach the valve on the end of the blue hose of the gauge set to the low-side fitting found on the large-diameter air conditioning line. Attach the red high-side valve on the end of the red hose on the gauge set to the high-side fitting on the small-diameter air conditioning line. Close the service valves on the gauge assembly and open the valves on the ends of the hoses by turning their knobs all the way in until they stop.
Screw the valve on the end of the yellow service hose on the gauge set to the inlet of the vacuum pump. Turn the vacuum pump on and open the service valves on the gauge assembly. Allow the vacuum pump to run for one hour to pull all of the moisture and air from the system.
Turn the vacuum pump off. Close the service valves and remove the vacuum pump from the yellow hose. Attache a can tap to the yellow hose and screw a can of refrigerant into the tap. Turn the thumbscrew on the tap in until it stops. Unscrew the thumbscrew to fully open the can of refrigerant. Open the blue service valve on the gauge assembly and start the engine. Turn the air conditioner on and set it for max air conditioning.
Allow the refrigerant in the can to empty into the system, then close the service valve. Remove the empty can from the tap and install another can. Open the can using the thumbscrew and open the service valve. Allow the second can to empty into the system. You will not use all of your third and final can of refrigerant. The Malibu air-conditioning system holds 28 ounces of refrigerant. Each can is 12 ounces. Add 1/4 of the third can, therefore; then close the service valve. The system is now full. Check for leaks and test drive the Malibu to verify the system functions correctly.
