These drawings illustrate
conditions you may observe
in the sight glass window.
A roof mounted condenser or AC unit assembly often
includes a roof mounted receiver-drier (and sight
glass) close to the condenser.
Preventive Maintenance Worksheet
Please feel free to modify or copy the worksheet in Figure 7-9. Actual vehicle use,
mileage, operating conditions, and maintenance budget may influence service
The purpose of these brief inspection procedures is for vehicle system maintenance
and to determine if further, more detailed service is required. The uses of a manifold
gauge set, system troubleshooting, recovery, flushing, evacuating, and charging are
explained in the next chapter.
High usage and operating condition variations are tough on air conditioning and
heater components. You should establish and follow regular inspection and
maintenance procedures to improve overall system function and component service
The typical inspection should not take more than 15 to 20 minutes unless
component replacement and/or complete system evacuation and recharging is
warranted. The survey results shown in Figure 7-1, indicate belts, compressor clutch
assembly, condenser, and refrigerant lines are the most frequent problem areas.
However, your own experience with service and maintenance may vary from survey
Inspection should first be visual and by feel. Some of your electrical system
inspection will be done as you inspect other components (checking leads,
connections, and for loose wires). When you check the electrical circuit, begin with
the engine off but ignition on. A system performance inspection with the engine
running and system on really combines electrical and AC or heater system function.