Air Conditioning: Overview Lexus GS III

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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 cool water. CAUTION: Do not rub your eyes or skin. Apply clean petroleum jelly to the skin. Go immediately to a physician or hospital 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 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 If the high pressure valves opened, refrigerant flows in the reverse direction and could cause the charging cylinder to rupture, so open and close the only low pressure valve.
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. SUPPLEMENTAL RESTRAINT SYSTEM (SRS) The LEXUS GS430/GS300 is equipped with an SRS (Supplemental Restraint System) such as the driver and passenger airbag. Failure to carry out service operations in the correct sequence could cause the SRS to unexpectedly deployed during servicing, possibly leading to a serious accident. Further, if a mistake is made in servicing the SRS, it is possible the SRS may fail to operate when required. Before servicing (including removal or installation of parts, inspection or replacement), be sure to read the following item carefully, then follow the correct procedure described in repair information.

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1. INSPECT REFRIGERANT VOLUME Observe the sight glass on the liquid tube. Test conditions: Running engine at 1,500 RPM Blower speed control switch at "HI" position A/C switch ON Temperature control dial at "COOL" position Fully open the doors *: 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 - 35 °C (86 - 95 °F) Engine running at 2,000 RPM Blower speed control switch at "HI" position Temperature control dial on "COOL" position HINT: It should be noted that the gauge indications may vary slightly due to ambient temperature conditions. Normally functioning refrigeration system. Gauge reading: Low pressure side: 0.15 - 0.25 MPa (1.5 - 2.5 kgf/cm 2 ) High pressure side: 1.37 - 1.57 MPa (14 - 15 kgf/cm 2 ) Moisture present in refrigeration system. Insufficient cooling Poor circulation of refrigerant Refrigerant does not circulate Refrigerant overcharged or insufficient cooling of condenser Air present in refrigeration system Expansion valve improperly Defective compression compressor
3. INSPECT IDLE-UP SPEED Warm up engine Inspect idle-up speed when the these conditions are established. Test conditions: Blower speed control switch at "HI" position Temperature control dial at "COOL" position A/C switch ON Put gear shift in neutral GS300: IDLE-UP SPEED Magnetic clutch condition Idle-up speed Magnetic clutch not engaged 700 +/- 50 rpm Magnetic clutch engaged 800 +/- 50 rpm If idle speed is not as specified, check the idle control system. GS430: IDLE-UP SPEED (GS430) Magnetic clutch condition Idle-up speed Magnetic clutch not engaged 750 +/- 50 rpm Magnetic clutch engaged 800 +/- 50 rpm If idle speed is not as specified, check the idle control system.
4. INSPECT FOR LEAKAGE OF REFRIGERANT Perform in these conditions. Stop engine Secure good ventilation (If the gas leak detector may not react volatile gases which are not refrigerant, such as evaporated gasoline and exhaust gas) Repeat the test 2 or 3 times Make sure that there is some refrigerant remaining in the refrigeration system. When compressor is OFF: approx. 392 - 588 kPa (4 - 6 kgf.cm 2 , 57 - 85 psi) Bring the gas leak detector close to the drain hose before performing the test. HINT: After the blower motor has stopped, leave the cooling for more than 15 minutes. Expose the gas leak detector sensor under the drain hose. When bring the gas leak detector close to the drain hose, make sure that the gas leak detector does not react to the volatile gases. If such reaction is unavoidable, the vehicle must be lifted up. If gas leak is not detected on the drain hose, remove the blower resistor from the cooling unit. Then insert the gas leak detector sensor into the unit and perform the test. Disconnect the connector and leave the pressure switch for approx. 20 minutes. Then bring the gas leak detector close to the pressure switch and perform the test. Bring the gas leak detector close to the refrigerant lines.

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1. CONNECT QUICK DISCONNECT ADAPTER TO CHARGING HOSES
2. REMOVE CAPS FROM SERVICE VALVES ON REFRIGERANT LINES
3. SET ON MANIFOLD GAUGE SET Close both hand valves of manifold gauge set. Connect the quick disconnect adapters to the service valves.
4. EVACUATE AIR FROM REFRIGERATION SYSTEM Connect the vacuum pump adapter to the vacuum pump. Connect the center hose of the manifold gauge set to the vacuum pump adapter. Open both the high and low hand valves and run the vacuum pump. After 10 minutes or more, check that the low pressure gauge indicates 750 mmHg (30 in. Hg) or more. HINT: If the reading is 750 mmHg (30 in. Hg) or more, close both hand valves of manifold gauge set and stop the vacuum pump. Check the system for leaks and repair if necessary. Close both the high and low hand valves and stop the vacuum pump. Leave the system in this condition for 5 minutes or more and check that there is no gauge indicator.

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1. INSTALL CHARGING CYLINDER HINT: When handling the charging cylinder, always follow the directions given in the instruction manual. Charge the proper amount of refrigerant into the charging cylinder. Connect the center hose to the charging cylinder. CAUTION: Do not open both high and low hand valves of manifold gauge set. Open the valve of charging cylinder. Press the valve core on the side of manifold gauge and expel the air inside of the center hose.
2. INSPECT REFRIGERATION SYSTEM FOR LEAKS Open the high pressure hand valve and charge refrigerant. When the low pressure gauge indicates 98 kPa (1 kgf/cm 2 , 14 psi) close the high pressure hand valve. Using a gas leak detector, check the system for leakage. If leak is found, repair the faulty component or connection. CAUTION: Use the refrigerant recovery/recycling machine to recover the refrigerant whenever replacing parts.
3. INSTALL CHARGING CYLINDER HINT: When handling the charging cylinder, always follow the directions given in the instruction manual. Charge the proper amount of refrigerant into the charging cylinder. Connect the center hose to the charging cylinder. CAUTION: Do not open both high and low hand valves of manifold gauge set. Open the valve of charging cylinder. Press the valve core on the side of manifold gauge and expel the air inside of the center hose. A fully charged system is indicated by the sight glass being free of any bubbles.
4. SET OFF MANIFOLD GAUGE SET Close both hand valves of manifold gauge set. Disconnect the quick disconnect adapters from the service valves.
5. INSTALL CAPS TO SERVICE VALVES ON REFRIGERANT LINES

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1. INSPECT DRIVE BELT'S INSTALLATION CONDITION Check that the drive belt fits properly in the ribbed grooves.
2. INSPECT DRIVE BELT TENSION Check that the arrow mark on the belt tensioner falls within area "A" of the scale. If it is out side area "A", replace the drive belt. HINT: When a new belt is installed, it should lie within area B.

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1. GS 300: REMOVE DRIVE BELT Loosen the drive belt tension by turning the drive belt tensioner clockwise and remove the drive belt.
2. GS 430: REMOVE DRIVE BELT Loosen the drive belt tension by turning the drive belt tensioner counterclockwise and remove the drive belt.

See also:
• BLOWER MOTOR CIRCUIT