Subaru XT 1988 Service Manual page 1041

•
AIR CONDITIONING SYSTEM
4-7
a. The bubbles seen through the sight glass are influenced
by the ambient temperature. Since the bubbles are hard to
show up in comparatively low temperatures below 20
0
e
(68° F), it is possible that a slightly larger amount of refriger-
ant would be filled, if supplied according to the sight glass. Be
sure to recheck the amount when it exceeds 20
0
e
(68°F). In
higher temperature the bubbles are easy to show up.
b. When the screen in the receiver drier is clogged, the bubbles
will appear even if the amount of refrigerant is normal. In
this case, the outlet side pipe of the receiver drier becomes
considerably cold.
Performance test
Check for the amount of refrigerant in the system can be madp
by measuring pressure on discharge side.
The correct amount of refrigerant is in the system. if pressure
on the discharge side is within the specified range. For details,
refer to "Performance Test" described later.
Overcharging will show up in higher pressure on discharge side.
COMPRESSOR OIL LEVEL CHECK
The oil used to lubricate compressor circulates into system
with refrigerant gas while compressor is operating. If a con-
siderable amount of leakage of refrigerant gas happens. the
leakage of compressor oil is also considered. There will be no
compressor oil leakage from a completely sealed system. When
system operates under satisfying condition. the compressor oil
level check is unnecessary.
1) Operate compressor at engine speed from 1 ,000 rpm to
1,500 rpm with controls set for maximum cooling and high
blower speed for about 10 minutes in order to return com-
pressor oil to compressor.
2) Stop the engine and discharge refrigerant of system and
then remove compressor from the car.
3) When exchanging the compressor for new one which
contains 150 cm
3
(150 cc, 9.15 cu in) oil, drain 80 cm
3
(80 cc, 4.88 cu in) oil from it respectively or adjust the
amount of oil to the same of the removed compressor.
4) If the oil separator is not available, control the quantity
of oil in accordance with the following table, when charging
compressor oil into the system from suction port of com-
pressor by using funnel as below picture.
L4498
When checking the level of compressor oil or when replacing
Fig. 25
any component part of the system, use the following service
procedure. This facilitates to return oil to compressor.
19