You will need a charging hose with a gauge, and a can or three of R134a refrigerant. Wear eye protection and handle with care.
- To begin, you need to adjust the ambient temperature arrow on the
gauge to the approximate temperature of the air outside, if possible with your gauge.
- Turn on the vehicle, and turn the A/C to high.
- Attach the blue charging hose to the low-pressure line, or the bigger of the two metal hoses.
- Once attached, check the gauge. If the indicator is in the green area,
your system is fine. If it is
below the green area, screw on a can of refrigerant and charge the system until the gauge reads in the green.
Steps that a tech will do if you take your car to a shop:
• A temperature sensor is
inserted into the AC vent and the system's efficiency is tested.
The high-pressure side of the system is connected to the
recycling-recharging testing machine, then the low-pressure side.
The machine reclaims and stores the refrigerant. The system is then run
under a vacuum for 30 minutes to test for leaks. This process also
removes accumulated moisture.
• If all is well, the refrigerant
is reintroduced into the system, and topped off as required.
The sight glass on the evaporator is literally a window into the AC
system. If the window is not clear, or bubbles are visible, this can
indicate system trouble.