GMC Chevrolet Camaro 1998 Service Manual page 135

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HVAC
Florescent Leak Detection Method
Tools Required
• Tracer Dye
• Tracer Dye Injector
• High Intensity Black Light
The R· 134a refrigerant is uniquely different from the
R-12 used in the past and may require additional
methods for leak detection. The R-134a molecule is
smaller than the R-12 molecule and can leak through
smaller openings. R-134a also does not contain
chlorine, which is easily detected using the black light.
The efflorescence leak detection method is meant
to be used in conjunction with the electronic method,
and will pinpoint smaller leaks. The R-134a takes
time to work. Depending on the rate of the leak, the
dye may take up to 7 days to become visible.
Liquid· Leak Detection/Pressure Testing
Methods
Due to their lack of sensitivity and restricted visibility in
today's refrigerant systems, liquid/bubble leak
detectors have very limited usefulness. Therefore, the
liquid leak detection/pressure testing methods are
not recommended for this vehicle.
Service Port Seal/Cap
The primary seal for the service ports is the sealing
cap. The cap contains a specially designed 0-ring or
gasket which provides a leak free seal. Should the
cap be loose, missing, or the wrong usage, a loss of
refrigerant could result.
HVAC System - Manual 1-25
VDOT A/C System Diagnosis
The V5 and V7 compressors are variable displacement
compressors. The V5 and V7 compressors match
the air conditioning demand by changing the
compressor stroke instead of cycling the compressor
clutch. A control valve is located in the rear head
of the compressor. The control valve completes the
following functions:
• Senses the low side pressure.
• Causes the compressor mechanism to change
stroke.
Bec.ause the compressor always runs and the system
does not cycle, these diagnostic procedures differ
from procedures that are used for fixed displacement
systems.
Preliminary Checks
• Inspect the A/C fuse. Replace as necessary.
• Inspect the A/C blower operation. Repair/replace
as necessary.
• Inspect the clutch coil electrical connection.
Repair/replace as necessary.
• Inspect the drive belt. Replace the drive belt if it is
damaged or missing.
• Inspect the operation of the cooling tans.
Repair/replace as necessary.
• Inspect the condenser for restricted air flow. Clean
the condenser as necessary.
The A/C system is operating properly if the discharge
air temperature and compressor pressures are
equal to those in the System Performance Test
Refer to the following tables when you are diagnosing
VDOT A/C system insufficient cooling complaints.
VDOT Refrigerant Charge
Step
Action
Value(s) Yes
No
DEFINITION: The A/C system is blowing warm air. Check the refrigerant for a low charge.
Were you sent here from the VDOT Diagnostic.
Go to the VDOT
1 System Check? -
System
Go to Step 2 Performance table
With the ignition in the OFF position, connect the
Go to the
2
A/C gauges.
345 kPa
Compressor
Are the high and low side pressures equal to (or) above
(50 psi)
Clutch
the value specified? Engagement table Go to Step 3
1. Add 0.45 kg (1 lb of R-134a).
3
2. Check the system for .leaks.
-
Is there a leak? Go to Step 6
Go to Step 4
4
Are the high and low side pressures within the 69-345 kPa
specified range? (10-50 psi) System OK
Go to Step 5
5
Repair the leak.
- -
Is the repair complete? Go to Step 6
Recover and recharge the A/C system. Refer to
Go to the
6
Refrigerant Recovery and Recharging
345 kPa
Compressor
Are the high and low side pressures above the value
(50 psi)
Clutch
specified? System OK
Engagement table