Air Conditioning System: Diagnosis Subaru Forester SF рестайлинг

Inspection

The following points should be kept in mind when conducting 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 and 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.

Clean Connections Before Testing

Before testing, use a clean shop towel to wipe off refrigerant 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.

Leak Test - High-Pressure Side

Operate the A/C system for approx. 10 minutes, then turn the engine off and begin the leak test.

Scheme 6

Scheme 7

Scheme 8

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 each tube connection.
2. Check the area: Check the area where the fitting meets the tube. (Scheme 6): Probing Where Fitting Meets Tube For Leaks Check the area where the two parts of the fitting join each other. (Scheme 7): Probing Where Two Parts Of Fitting Join Each Other For Leaks Check the area where the nut meets the tube. (Scheme 8): Probing Where Nut Meets Tube For Leaks
3. Check the area of the 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 compressor.
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 compressor 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].

Scheme 9

1. Begin at the connection of the low-pressure tube to the evaporator, and work your way along the low-pressure of the system to the compressor. There are three places to check on each tube connection.
2. Check the area: Check the area where the fitting joins the tube. Check the area where the two parts of the fitting join each other. (Scheme 9): Probing Fitting Flanges For Leaks

Scheme 10

1. Visually inspect the rubber portions of the flexible hoses for cracking. Probe the rubber section, including the ends of any insulators or protectors which may cover sections of the rubber hose, and near the ends where the rubber meets the metal collar. NOTE: Be certain to move the probe slowly [approximately 25 mm (1 in) per second] when probing along any length of hose or tube. (Scheme 10): Probing Along Length Of Hose Or Tube For Leaks

Scheme 11

1. Use one or both of the following methods to check the evaporator assembly.
2. Remove the drain hose from the case drain nipple. Hold the probe at the end of the case drain nipple for at least 10 seconds. Be certain to reconnect the drain hose when finished.
3. With the ignition key in the "ACC" position, run the blower on high speed for 1 minute, then turn the blower off. Place the probe in the center instrument panel vent, and turn the blower on low speed for 1 to 2 seconds, then turn the blower off. Leave the probe in the vent for at least 10 seconds. (Scheme 11): Probing Center Instrument Panel Vent For Freon Leaks

1. Make sure the condenser fins are free from dust and insects. If the fins are clogged, clean by blowing air or water through them. NOTE: To prevent dust and water from getting into the condenser, this work must be done when the condenser is installed in an actual vehicle.
2. Check the condenser to see if it shows any sign of oil. Should oil ooze or gas leak from the condenser replace it with a new one.

Scheme 12

1. Disconnect battery negative terminal.
2. Discharge refrigerant using refrigerant recovery system, see «DISCHARGE THE SYSTEM»(ref-175292-S13290396852005042000000).
3. Disconnect pressure switch harness (A).
4. Disconnect pipes (B).
5. Remove mounting bolt (C) and remove receiver drier. CAUTION: The receiver drier contains a desiccant. Be sure to put a blind plug in the detached receiver drier to protect it from moisture. (Scheme 12): Removing Receiver Drier
6. Install the receiver drier in the reverse order of removal.
7. Charge refrigerant. See «EVACUATING AND CHARGING»(ref-175292-S25885800222005042000000).

Scheme 13

Scheme 14

Scheme 15

1. Disconnect battery negative terminal.
2. Discharge refrigerant using refrigerant recovery system, see «DISCHARGE THE SYSTEM»(ref-175292-S13290396852005042000000).
3. Remove bolt then disconnect discharge pipe and suction pipe. (Scheme 13): Removing Discharge Pipe & Suction Pipe
4. Remove glove box. (Scheme 14): Removing Glove Box
5. Disconnect the harness connector from intake unit.
6. Disconnect drain hose.
7. Remove intake unit mounting bolt and nut. (Scheme 15): Removing Intake Unit
8. Install the intake unit in the reverse order of removal.
9. Charge refrigerant. See «EVACUATING AND CHARGING»(ref-175292-S25885800222005042000000).

Scheme 16

Scheme 17

1. Remove thermistor (A) from intake unit case.
2. Remove some screws then separate intake unit case.
3. Remove thermistor from clip with the evaporator. (Scheme 16): Removing Evaporator From Intake Unit Case (1 Of 2)
4. Remove the block expansion valve (A) from pipes. (Scheme 17): Removing Evaporator From Intake Unit Case (2 Of 2)
5. Check to see if the evaporator fins are clogged. If they are, clean them with compressed air. CAUTION: Water must never be used to clean the evaporator.
6. Check parts that have been removed for cracks or scratches, and repair or replace them with new ones, if necessary.
7. Reassemble the intake unit in the reverse order of disassembly. NOTE: Confirm that the O-ring is inserted in the specified position.

Scheme 18

1. Disconnect battery negative terminal.
2. Disconnect harness connector from fan motor.
3. Remove condenser fan bolts from radiator. (Scheme 18): Removing Condenser Fan Bolts From Radiator
4. Pull condenser fan assembly.
5. Install the condenser fan assembly in the reverse order of removal.

Check continuity of A/C relay and Sub fan relay with a circuit tester (ohm range) according to the following figure.

Checking Continuity Of A/C Relay And Sub Fan Relay. Scheme 19

Note. Pressure switch is attached to receiver dryer. It has two built-in switches.

Identifying Pressure Switch. Scheme 20

Scheme 21

1. Remove cap from high-pressure line service valve, and connect gauge manifold to service valve.
2. Disconnect pressure switch harness connector, and check pressure switch for proper ON-OFF operation. Use a circuit tester. (Scheme 21): Checking Pressure Switch For Proper On-Off Operation

Scheme 22

1. Remove the four upper clips from body panel. To facilitate removal, press portion shown in the figure using screwdriver while lightly pulling front grille. (Scheme 22): Removing & Installing Front Grille
2. Install in the reverse order of removal. NOTE: Attach all clips to grille. Align them with clip hole in body and push them into place.

PERFORMANCE TEST DIAGNOSIS

In various conditions caused to other air conditioning system, the characteristics revealed on manifold gauge reading are shown in the following.

As to the method of a performance test, refer to the item of "Performance Test".

Each shaded area on the following tables indicates a reading of the normal system when the temperature of outside air is 32.5°C (91°F).

Performance Test Diagnosis Chart (1 Of 3). Scheme 23

Performance Test Diagnosis Chart (2 Of 3). Scheme 24

Performance Test Diagnosis Chart (3 Of 3). Scheme 25

Blower Motor Diagnosis Chart. Scheme 26

Compressor Diagnosis Chart. Scheme 27

Compressor Clutch Diagnosis Chart (1 Of 2). Scheme 28

Compressor Clutch Diagnosis Chart (2 Of 2). Scheme 29