Air Conditioning System: Overview Lexus RX II

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1. DO NOT HANDLE REFRIGERANT IN AN ENCLOSED AREA OR NEAR AN OPEN FLAME
2. ALWAYS WEAR EYE PROTECTION
3. BE CAREFUL NOT TO GET LIQUID REFRIGERANT IN YOUR EYES OR ON YOUR SKIN If liquid refrigerant gets in your eyes or on your skin. Wash the area with lots of cold water. CAUTION: Do not rub your eyes or skin. Apply clean petroleum jelly to the skin. Go immediately to a hospital or see a physician for professional treatment.
4. NEVER HEAT CONTAINER OR EXPOSE IT TO NAKED FLAME
5. BE CAREFUL NOT TO DROP CONTAINER AND NOT TO APPLY PHYSICAL SHOCKS TO IT
6. DO NOT OPERATE COMPRESSOR WITHOUT ENOUGH REFRIGERANT IN REFRIGERANT SYSTEM If there is not enough refrigerant in the refrigerant system, oil lubrication will be insufficient and compressor may burnout may occur, so take care to avoid this, necessary care should be taken.
7. DO NOT OPEN HIGH PRESSURE MANIFOLD VALVE WHILE COMPRESSOR IS OPERATING Open and close the only low pressure valve. If the high pressure valves are opened, refrigerant flows in the reverse direction and cause the charging cylinder to rupture.
8. BE CAREFUL NOT TO OVERCHARGE SYSTEM WITH REFRIGERANT If refrigerant is overcharged, it causes problems such as insufficient cooling, poor fuel economy, engine overheating, etc.
9. DO NOT OPERATE ENGINE AND COMPRESSOR WITH NO REFRIGERANT IS FILLED CAUTION: This may damage the inside of the compressor because the compressor parts always moves regardless of whether the A/C system is turned on or off.

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1. INSPECT REFRIGERANT VOLUME Check the sight glass on the liquid tube sub-assy A. Test conditions: Engine is running at 1,500 RPM Blower speed control switch is at "HI" A/C switch is ON Temperature control dial is at "MAX. COOL" Doors are fully open. SYMPTOM CHART Item Symptom Amount of Refrigerant Corrective Actions 1 Bubbles exist Insufficient (1) Check for gas leakage and repair if necessary Add refrigerant until bubbles disappear 2 No bubbles exist Empty insufficient or excessive Refer to 3 & 4 3 No temperature difference between compressor inlet and outlet Empty or nearly empty Check for gas leakage with gas leak detector and repair if necessary Add refrigerant until bubbles disappear 4 Considerable temperature difference between compressor inlet and outlet. Proper or excessive Refer to 5 & 6 5 Immediately after air conditioning is turned off, refrigerant clears Excessive Discharge refrigerant Remove air and supply proper amount of purified refrigerant 6 Immediately after air conditioning is turned off, refrigerant foams and then becomes clear Proper - (1) Bubbles in the sight glass with ambient temperatures higher than usual can be considered normal if cooling is sufficient.
2. INSPECT REFRIGERANT PRESSURE WITH MANIFOLD GAUGE SET This is a method in which the trouble is located by using a manifold gauge set. Read the manifold gauge pressure when these conditions are established. Test conditions: Temperature at the air inlet with the switch set at RECIRC is 30 to 35 °C (86 to 95 °F) Engine is running at 1,500 RPM Blower speed control switch is at "HI" Temperature control dial is at "COOL" A/C switch is ON Doors are fully open. Normally functioning refrigeration system. Gauge reading: Low pressure side: 0.15 to 0.25 MPa (1.5 to 2.5 kgf/cm 2 ) High pressure side: 1.37 to 1.57 MPa (14 to 16 kgf/cm 2 ) Moisture present in refrigeration system. SYMPTOM CHART Symptom Probable cause Diagnosis Remedy During operation, pressure on low pressure side cycles between normal and vacuum Moisture in refrigeration system freezes at expansion valve orifice, causing a temporary stop of cycle. However, when it melts, normal state is restored. Drier in oversaturated state Moisture in refrigeration system freezes at expansion valve orifice and blocks circulation of refrigerant Replace condenser Remove moisture in cycle by repeatedly evacuating air Supply proper amount of new refrigerant Insufficient cooling SYMPTOM CHART Symptom Probable cause Diagnosis Corrective Actions Pressure is low on both low and high pressure sides Bubbles are seen through sight glass continuously Insufficient cooling performance Gas leakage in refrigeration system Insufficient refrigerant Refrigerant leaking Check for gas leakage and repair if necessary Supply proper amount of new refrigerant If indicated pressure value is close to 0 when connected to the gauge, create vacuum after inspecting and repairing the location of leakage. Poor circulation of refrigerant SYMPTOM CHART Symptom Probable cause Diagnosis Corrective Action Pressure is low on both low and high pressure sides Frost exists on pipe from condenser to unit Refrigerant flow is obstructed by dirt in the receiver Receiver is clogged Replace condenser Refrigerant does not circulate SYMPTOM CHART Symptom Probable cause Diagnosis Corrective Actions Vacuum is indicated on low pressure side and very low pressure is indicated on high pressure side Frost or dew is seen on piping on both sides of receiver/drier or expansion valve Refrigerant flow is obstructed by moisture or dirt in refrigeration system Refrigerant flow is obstructed by gas leak from expansion valve Refrigerant does not circulate Check the expansion valve Clean out dirt in expansion valve by blowing air Replace condenser Evaporate air and supply proper amount of new refrigerant. For gas leakage from expansion valve, replace expansion valve Refrigerant is overcharged or cooling of effectiveness of condenser is insufficient SYMPTOM CHART Symptom Probable cause Diagnosis Corrective Actions Pressure is too high on both low and high pressure sides No air bubbles are seen through sight glass even when engine rpm lowers Unable to develop sufficient performance due to excessive use of refrigeration system Cooling effectiveness of condenser is insufficient. Excessive refrigerant in cycle-->excessive refrigerant is supplied Condenser cooling effectiveness is insufficient-->condenser fins are clogged at cooling fan Clean condenser Check cooling fan with cooling fan motor operation If (1) and (2) are in normal state, check the amount of refrigerant and supply proper amount o refrigerant Air present in refrigeration system SYMPTOM CHART Symptom Probable cause Diagnosis Corrective Actions Pressure is too high on both low and the high pressure sides The low pressure piping is too hot to touch Bubbles can be seen through sight glass Air in system Air present in refrigeration system Insufficient vacuum purging Check compressor oil to see if it is dirty or insufficient Evacuate air and supply new refrigerant Expansion valve malfunction SYMPTOM CHART Symptom Probable cause Diagnosis Corrective Actions Pressure is too high on both low and high pressure sides Frost or large amount of dew on piping on low pressure side Trouble in expansion valve Excessive refrigerant in low pressure piping Expansion valve opened too wide Check expansion valve Defective compression compressor SYMPTOM CHART Symptom Probable cause Diagnosis Corrective Actions Pressure is too high both on low and high pressure sides Pressure is too low on high pressure side Internal leak in compressor Compression failure Leakage from damaged valve or broken sliding parts Repair or replace compressor Gauge readings (Reference)

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1. DISCHARGE REFRIGERANT FROM REFRIGERATION SYSTEM Turn the A/C switch ON. Operating the cooler compressor at the engine RPM of approx. 1,000 for 5 to 6 minutes, circulate the refrigerant and collect compressor oil remaining in each component into the cooler compressor as much as possible. Stop the engine. Using SST (s) let the refrigerant gas out. SST 07110-58060 (07117-58080, 07117-58090, 07117-78050, 07117-88060, 07117-88070, 07117-88080)
2. CHARGE REFRIGERANT Using a vacuum pump, perform a vacuum purging. Using SST (s) charge refrigerant, HFC-134a (R134a). Standard: 600 +/- 50 g (21.15 +/- 1.76 oz.) SST 07110-58060 (07117-58060, 07117-58070, 07117-58080, 07117-58090, 07117-78050, 07117-88060, 07117-88070, 07117-88080) NOTE: Do not start the engine before charging with refrigerant as the cooler compressor doesn't work properly without any refrigerant, which causes the compressor to overheat.
3. WARM UP ENGINE NOTE: Warm up the engine at less than 2000 RPM for 2 minutes or more after charging with refrigerant.
4. INSPECT LEAKAGE OF REFRIGERANT Using a gas leak detector, check for leakage of refrigerant.

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1. REMOVE CONSOLE PANEL UPPER FRONT (See «REPLACEMENT» )
2. REMOVE INSTRUMENT PANEL FINISH PANEL LOWER (See «REPLACEMENT» )
3. REMOVE RADIO RECEIVER ASSEMBLY W/BRACKET (See «REPLACEMENT» )
4. REMOVE CENTER CLUSTER INTEGRATION SWITCH ASSY Remove the 2 bolts. Release the 6 clip fittings. Remove the connector and center cluster integration switch assy.
5. REMOVE HEATER CONTROL BASE BRACKET LH Remove the 2 bolts and heater control base bracket LH.
6. REMOVE HEATER CONTROL BASE BRACKET RH Remove the 2 bolts and heater control base bracket RH.
7. REMOVE HEATER CONTROL HOUSING SUB-ASSY Remove the 4 screws and heater control housing sub-assy.
8. REMOVE MULTI INFORMATION DISPLAY SUB-ASSY Release the lock of the connector and disconnect the cable. Remove the 2 screws and multi information display sub-assy.

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1. REMOVE V (COOLER COMPRESSOR TO CRANKSHAFT PULLEY) BELT NO.1 Loosen the bolt C. Loosen the bolt A. Loosen the bolt B and remove the V (cooler compressor to crankshaft pulley) belt No.1.
2. INSTALL V (COOLER COMPRESSOR TO CRANKSHAFT PULLEY) BELT NO.1 Temporarily install the V (cooler compressor to crankshaft pulley) belt No.1 as illustrated in (Scheme 312).
3. ADJUST V (COOLER COMPRESSOR TO CRANKSHAFT PULLEY) BELT NO.1 Apply drive belt tension by turning the bolt B. Drive belt tension: New Belt: 170 +/- 10 lbf Used belt: 125 +/- 10 lbf HINT: "New belt" refers to a belt which has been used on a running engine at idling for 5 minutes or more. "Used belt" refers to a belt which has used on a running engine at idling for 5 minutes or more. Check that the drive belt fits properly in the ribbed grooves.
4. FULLY TIGHTEN V (COOLER COMPRESSOR TO CRANKSHAFT PULLEY) BELT NO.1 Tighten the bolt A. Torque: 18 N.m (183 kgf.cm, 13 ft.lbf) Tighten the bolt C. Torque: 58 N.m (591 kgf.cm, 43 ft.lbf)

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See also:
• REPLACEMENT
• REPLACEMENT
• REPLACEMENT
• ON-VEHICLE INSPECTION