A/C System Performance Test

A/C System Performance Test

1. Ensure air flow from blower fans is correct in relation to switch position.
2. With engine running check the following:
a. Compressor clutch engages and disengages correctly during operation of control switch.
b. Radiator cooling fan starts operating when compressor clutch engages.
c. Compressor drive belt is adjusted correctly and does not slip at higher engine speeds, idle, or during sudden acceleration with compressor clutch engaged.
3. Run engine at 1000 RPM and check for foaming or bubbles in receiver-dryer sight glass.
4. Slowly increase engine speed to 1800 RPM and check again for foaming or bubbles. Slight foaming is normal with ambient temperatures below 70°F.
5. Check for heavy frosting on connector union housing. Suction area is normally cold and slightly frosted.
6. Inspect A/C lines for sudden temperature changes, indicating blockages at that point.
7. Place thermometer at air outlets and road test vehicle, noting temperature changes with air conditioning switched off and on.
8. Ensure condenser coils are free of foreign matter which might block air flow, and clean as necessary.
9. If system does not perform as described, conduct performance and system operation tests.