1997 SUBARU LEGACY check engine

G4M0596
7. Evacuating and Charging
The following points should be kept in mind when evacu-
ating and charging with a manifold gauge set.
1) Be certain that goggles and gloves are worn.
2) If bulk refrigerant [13.6 kg (30 lb) canister] is used, be
certain to weigh the charge amount carefully, using the
correct equipment, to avoid overcharging the system.
3) The charging procedure described in this section
begins by chargingliquidrefrigerant into the high- pres-
sure side of the systemwith the engine off.The proce-
dure is completed by charging refrigerantvaporinto the
low-pressure side of the system with the engine running.
CAUTION:
Never open the high-pressure manifold valve when the
engine is running.
G4M0597
1. CONNECT THE GAUGE SET
1) Close the high- and low-pressure manifold valves.
2) Attach the low-pressure manifold hose to the low- pres-
sure service port on the vehicle. Check the low- pressure
gauge. If more than 68.6 kPa (0.70 kg/cm
2, 10 psi) is
indicated, discharge the system prior to charging.
3) Attach the high-pressure manifold hose to the high-
pressure service port on the vehicle.
4) Connect the center hose from the manifold to the
vacuum pump.
5) Turn on the vacuum pump.
6) Slowly open the low-pressure manifold valve.
7) When the low-pressure gauge reaches approximately
66.43 kPa (498.3 mmHg, 19.62 inHg), slowly open the
high-pressure manifold valve.
G4M0598
8) Maintain a minimum vacuum level of 100.56 kPa (754.4
mmHg, 29.70 inHg) for a minimum of 15 minutes on a new
system or 30 minutes for an in-service system.
NOTE:
The gauge will read 4 kPa (25 mmHg, 1 inHg) less for
every 304.8 m (1,000 ft) above sea level.
19
4-7SERVICE PROCEDURE
7. Evacuating and Charging

G4M0604
4. INITIAL CHARGING THROUGH THE HIGH SIDE
1) Connect a tachometer to the engine.
2)With the engine off, start charging by slowly opening
the high-pressure manifold valve.
NOTE:
The initial charge rate can be increased by immersing the
can in lukewarm [Below 38°C (100°F)] water for a short
time.
G4M0605
5. CHECK THE GAUGE READINGS
When both the high- and low-pressure gauge readings are
about equal, or the HFC-134a source is empty, or the sys-
tem has been filled to specifications, close the high- pres-
sure manifold valve.
6. ADD ADDITIONAL CANS
If the HFC-134a source is exhausted, first close the high-
pressure manifold valve, second, close the can tap valve,
then slowly purge the refrigerant from the service hose by
loosening the fitting at the can tap. Repeat steps 15
through 19 as necessary.
G4M0606
7. COMPLETE CHARGING THROUGH THE LOW SIDE
1) Verify that the high-pressure manifold valve is closed
(should have already been closed).
2) Verify that the low-pressure manifold valve is closed
(should have already been closed).
G4M0607
3) With the A/C switch off and the windows rolled down,
start the engine and run at idle rpm.
4) Set the A/C controls on maximum cool and set the
blower speed on the highest setting.
5) Quickly turn the A/C switch on-off-on-off a few times to
prevent initial compressor damage due to“load shock.”
Finish this operation with the A/C switch in the ON position.
6) Raise engine rpm to approximately 1,500 rpm.
21
4-7SERVICE PROCEDURE
7. Evacuating and Charging

8. Leak Testing
The following points should be kept in mind when conduct-
ing a refrigerant leak test.
1) The A/C system to be tested must have an adequate
refrigerant charge to begin with.
2) The area where the leak test is conducted must be free
of wind and drafts, with still air being the ideal condition.
3) The atmosphere where the leak test is conducted must
be free of refrigerant contamination.
4) Operate the A/C system for approx. 10 minutes, then
turn the engine off an begin the leak test.
5) Refrigerant gas is heavier than air, therefore always
hold the probe below the connection being tested.
6) When checking for a leak along a length of hose or
tube, the leak detector probe must be moved slowly,
approx. 25 mm (1 in) per second making sure probe does
not come in contact with the component being tested.
7) When checking for a leak at a certain point, the leak
detector probe must be held at that point for at least 5
seconds.
G4M0609
1. CHECK THE SYSTEM PRESSURE
With gauges connected to the A/C system, operate the A/C
and confirm that the high side pressure is above 690 kPa
(7.03 kg/cm
2, 100 psi). If not, evacuate and charge the
system before leak checking (refer to evacuation and
charging sections).
2. CLEAN CONNECTIONS BEFORE TESTING
Before testing, use a clean shop towel to wipe off refriger-
ant oil, dirt, or foreign material from all of the connections
and components to be tested.
NOTE:
Since refrigerant oil absorbs refrigerant, excess oil on or
near a connection may falsely signal a leak.
B4M0089
3. CALIBRATE LEAK DETECTOR
Refer to the manufacturer’s instructions for the particular
type of detector used and calibrate the instrument.
CAUTION:
Always make sure that the probe tip filter is clean and
free of contamination.
23
4-7SERVICE PROCEDURE
8. Leak Testing

G4M0612
4. LEAK TEST — HIGH-PRESSURE SIDE
Operate the A/C system for approx. 10 minutes, then turn
the engine off and begin the leak test.
1) Begin at the connection of the high-pressure tube to the
evaporator, and work your way along the high- pressure
side of the system to the compressor. There are three
places to check on each tube connection.
2) Check the area.
(1) Check the area where the fitting joins the tube.
G4M0613
(2) Check the area where the two parts of the fitting
join each other.
G4M0614
(3) Check the area where the nut joins the tube.
3) Check the area of the sight glass and pressure switch
(dual switch), and also check the seams of the receiver
drier.
4) Check the connections of the tubes to the condenser,
and also check any welded joints on the condenser.
CAUTION:
An oily area on the fins of the condenser may indicate
a leak.
5) Check the area where the hoses attach to the compres-
sor.
6) Check around the machined portions of the compressor
(where the compressor sections join each other).
7) If equipped, check the thermal limiter on the compres-
sor housing.
8) Check the compressor shaft seal by probing near the
center of the compressor clutch pulley.
NOTE:
Some shaft seals have a very slight amount of normal
leakage [approximately 28 g (1.0 oz) per year].
24
4-7SERVICE PROCEDURE
8. Leak Testing

G4M0619
8. CHECK THE SERVICE PORT CAPS
Visually inspect the inside of the service port caps. Make
sure the rubber seal is in place on the inside of the caps.
Disconnect the gauges from the vehicle and install the
service port caps.
9. Lubrication
1. SYSTEM OIL STABILIZATION
Prior to opening the refrigerant system for repairs (except
compressor seizure) the system must be stabilized for cor-
rect oil replenishment.
Follow these procedures:
1) Engine speed set to 1,500 rpm
2) A/C“ON”
3) Air source to recirculate
4) Blower in 4th or high speed position
Make sure the air entering the evaporator is above
26.7°C (80°F).
The discharge (high) side pressure must be above
588 kPa (6 kg/cm
2, 85 psi).
5) Operate the A/C for 10 minutes.
2. SYSTEM DISCHARGE
Slowly, discharge the system starting with the high- pres-
sure side until the pressure drops below 345 kPa (3.52
kg/cm
2, 50 psi), then open the low-pressure side.
26
4-7SERVICE PROCEDURE
8. Leak Testing - 9. Lubrication

G4M0619
8. CHECK THE SERVICE PORT CAPS
Visually inspect the inside of the service port caps. Make
sure the rubber seal is in place on the inside of the caps.
Disconnect the gauges from the vehicle and install the
service port caps.
9. Lubrication
1. SYSTEM OIL STABILIZATION
Prior to opening the refrigerant system for repairs (except
compressor seizure) the system must be stabilized for cor-
rect oil replenishment.
Follow these procedures:
1) Engine speed set to 1,500 rpm
2) A/C“ON”
3) Air source to recirculate
4) Blower in 4th or high speed position
Make sure the air entering the evaporator is above
26.7°C (80°F).
The discharge (high) side pressure must be above
588 kPa (6 kg/cm
2, 85 psi).
5) Operate the A/C for 10 minutes.
2. SYSTEM DISCHARGE
Slowly, discharge the system starting with the high- pres-
sure side until the pressure drops below 345 kPa (3.52
kg/cm
2, 50 psi), then open the low-pressure side.
26
4-7SERVICE PROCEDURE
8. Leak Testing - 9. Lubrication

Pulley arrangement Tension mm (in)/98N (10 kg, 22 lb)
G4M0939
AB
*New belt:
7.0—9.0
(0.276—0.354)
Existing belt:
9.0—11.0
(0.354—0.433)*New belt:
7.5—8.5
(0.295—0.335)
Existing belt:
9.0—10.0
(0.354—0.394)
* When replacing belts with new ones, adjust tensions to
specification and then readjust to the same specification
after running engine for 5 minutes.
Figures in table refer to the number of grooves in pulleys.
C/P : Crankshaft pulley
ALT : Alternator pulley
P/S : Power steering oil pump pulley
A/C : Air conditioner compressor pulley
I/P : Idler pulley
G4M0634
CAUTION:
Ensure that the V-belt is aligned correctly. If it is not,
check for loose bolts.
The V-belt should not be too tight or too loose.
A belt which is too tight may break bearing or cause
gas to leak from the shaft seal. A belt which is too
loose slips, thereby causing the belt cut.
After completing the compressor installation and
testing the system operation, check and adjust the ten-
sion of both V-belts again.
B4M0761A
7) Install high-pressure hose
2(Flexible hose Pd).
Connect high-pressure hose with compressor.
CAUTION:
Be sure to apply compressor oil to the periphery of
O-ring.
B4M0761A
8) Install low-pressure hose
1(Flexible hose Ps).
Connect low-pressure hose with compressor.
CAUTION:
Be sure to apply compressor oil to the periphery of
O-ring.
33
4-7SERVICE PROCEDURE
11. Compressor

Condition Probable cause Corrective action
FAULTY CONDENSER
G4M0680
No cooling action;
Engine may overheat.
Suction line is very hot.Condenser is often
found not functioning
well.Check condenser
cooling fan.
Check condenser for
dirt accumulation.
Check engine cooling
system for overheat.
Check for refrigerant
overcharge.
If pressure remains
high in spite of all
above actions taken,
remove and inspect
the condenser for pos-
sible oil clogging.
HIGH-PRESSURE LINE BLOCKED
G4M0681
Insufficient cooling;
Frosted high-pressure
liquid line.Drier is clogged, or
restriction in high-pres-
sure line.1. Discharge system.
2. Remove receiver
drier or strainer and
replace it.
3. Evacuate and charge
system.
FAULTY COMPRESSOR
G4M0682
Insufficient cooling Internal problem is in
compressor, or dam-
aged gasket and valve.1. Discharge system.
2. Remove and check
compressor.
3. Repair or replace
compressor.
4. Check oil level.
5. Replace receiver
drier.
6. Evacuate and charge
system.
44
4-7DIAGNOSTICS
2. Performance Test Diagnosis