Opel 1900 1973, Service Manual

Page: 606 / 625

1973 OPEL SERVICE MANUAL
DIAGNOSIS
TROUBLE DIAGNOSIS
GUIDE
Insufficient Cooling
CHECK AIR FLOW
FAN DOES NOT RUN Correct fault.
FAN RUNS
Check air velocity.
NOT OK Clean evaporator inlets.
Clean evaporator core.
Clean evaporator outlets.
OK Check refrigeration (refer to Refrigeration
Diagnosis Guide).
MAINTENANCE AND ADJUSTMENTS
A D J U S T M E N T O F T H E R M O S T A T I C S W I T C H
The system makes use of a thermostatic switch with
a self-supporting air sensing capillary. This capillary
controls the switch by sensing the temperature of the
air leaving the evaporator tins.
Checking for Proper Operation
1. Install the gauge set, and set up the vehicle as
described under FUNCTIONAL TESTING SYS-
TEM in Refrigerant Components Section.
2. Movement of the temperature control knob
should result in a definite change in suction pressure
and cycling of the compressor clutch.
3. If compressor continues to operate regardless of
the knob adjustment it indicates that the switch
points are fused, which will lead to evaporator
freeze-up. The switch should be replaced.
Adjusting Switch
If after the foregoing checks, the switch seems to be
operating correctly, adjust for proper setting if neces-
sary, as follows:
1. Set up car as described in FUNCTIONAL
TESTING SYSTEM in Refrigerant Components
Section.
2.
The suction side of the system, read on the low
pressure gauge, should pull down to the pressure
shown in the chart in SPECIFICATIONS in Refrig-
erant Components Section.
3. Remove the duct assembly screws and
remove the duct assembly noting the position of the
air sensing capillary so that it can be reinstalled in
the same location as when removed. See Figure
190.
Figure Duct Assembly and Retaining Screws
Figure 1 Duct Assembly
4. Remove the thermostatic switch retaining screws
and remove switch. Remove the non-metal end plate
from the switch to gain access to the switch adjusting
screw. Check the screw for stripped or otherwise
damaged threads.