NG 900/9-3 AC Recharge
AC Recharge Overview
If the air from the vents does not seem cold enough but the air conditionning is still working, the A/C may not have been recharged for a long time, or there may be small leaks in the system. Joints between pipes and hoses depend on o-ring seals which often dry out and lose their elastic properties after a few years. For best operation, the system should be evacuated, recharged, and tested for leaks every few years(4-6) by an A/C service professional who can be trusted, but adding refrigerant is a simple process with no special tools required.
Testing the pressure and recharging the A/C is an easy job. A pair of cotton gloves and safety glasses should be used, just in case some of the refrigerant escapes during the recharge.
Auto part stores sell recharge kits which are basically a hose with two connections and a gauge in the middle. (example, Napa # BK7652982) Our cars use R134a refrigerant, and PAG-100 oil (NG900 w. Seiko-Seiki compressor) or PAG-46 oil (9-3 w. Sanden compressor)
Recharge the system through the low-pressure port, which has a cap that sticks up next to the radiator, near the battery.
NEVER try to connect a recharge kit to the high-pressure port behind the grille.
It is best to stay away from the high-pressure port completely because of the likelihood of injury if the refrigerant should erupt from that side of the system.
While charging the A/C system, the engine should be running, A/C at the lowest setting and doors or windows should be open. On cars that have ACC the display should read "LO" while charging.
One end of the charging hose snaps over the low pressure port. The other end of the hose screws down tight on top of the refrigerant container. The thumb screw at the container is screwed in to pierce the container seal, and then backed off to allow the refrigerant or the esther oil out. If adding oil, the can is held upside down. If adding refrigerant, right side up.