Chapter 8- Troubleshooting & Service Procedures
If you find particles of desiccant in the compressor,
remove and replace it and the receiver-drier. Be-
fore doing so, back flush other system components
(except the expansion valve) using a flushing kit. If
there are stem type valves and you isolate the
of refrigerant before you can disconnect and flush
system components (Chapter 9 ) describes the flush-
ing procedure). After flushing, reassemble the
components. Always check the oil level in the com-
pressor, even if you install a new or rebuilt unit.
Tighten all connections and evacuate the system.
Recharge the air conditioner with refrigerant and
check system operation and performance.
Rotary compressors have a limited oil reservoir.
Extra oil must be added for all truck installa-
Condenser Malfunction or System Overcharge
Gauge reading, condenser
malfunction or system over-
The air from vents in the cab may be warm. In R-
12 systems there can be bubbles in the sight glass.
The high pressure hoses and lines will be very hot.
Don't forget to check the engine cooling system
components--fan and drive belt, fan clutch opera-
tion, and the radiator shutter.
The condenser is not functioning correctly or there
may be an overcharge of refrigerant inside the
system. Another possibility is lack of (ram) air flow
through the condenser fins during testing. Engine
cooling system component malfunction can cause
high pressure by blocking air flow (radiator shut-
ter) or not providing air flow (fan clutch) in suffi-