Page 1 of 1111
AC2810
AC0W6±01
AC2811
N11084
Wrong Okay
HI LO HILO
± AIR CONDITIONINGAIR CONDITIONING SYSTEM
AC±1
2686 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
AIR CONDITIONING SYSTEM
PRECAUTION
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.
(a) Wash the area with lots of cool water.
CAUTION:
Do not rub your eyes or skin.
(b) Apply clean petroleum jelly to the skin.
(c) 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 lu-
brication 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 re-
verse direction and could cause the charging cylinder to rup-
ture, 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 insuffi-
cient cooling, poor fuel economy, engine overheating etc.
Page 17 of 1111
AC0WK±01
I02360
I02361
AC±24
± AIR CONDITIONINGAIR CONDITIONING UNIT
2709 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
REMOVAL
1. DISCHARGE REFRIGERANT FROM REFRIGERATION
SYSTEM
HINT:
At the time of installation, please refer to the following item.
Evacuate air from refrigeration system.
Charge system with refrigerant and inspect for leakage of refrig-
erant.
Specified amount: 600 ± 50 g (21.16 ± 1.76 oz.)
2. DRAIN ENGINE COOLANT FROM RADIATOR
HINT:
It is not necessary to drain out all coolant.
3. DISCONNECT LIQUID TUBE AND SUCTION HOSE
FROM A/C UNIT
Remove the bolt and slide the plate, then disconnect the both
tubes.
Torque: 10 N´m (100 kgf´cm, 7 ft´lbf)
NOTICE:
Cap the open fittings immediately to keep moisture or dirt
out of the system.
HINT:
At the time of installation, please refer to the following item.
Lubricate 2 new O±rings with compressor oil and install them
to the tubes.
4. DISCONNECT WATER HOSES FROM HEATER RA-
DIATOR PIPES
(a) Grips the claws of the hose clip and slide the hose clip
along the hose.
(b) Disconnect the water hose.
Page 19 of 1111
AC0WL±01
AC±26
± AIR CONDITIONINGAIR CONDITIONING UNIT
2711 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
DISASSEMBLY
1. REMOVE THESE PARTS:
(a) Wire harness
(b) Drain hose
2. REMOVE HEATER RADIATOR
(a) Remove the screw and clamp.
(b) Pull out the heater radiator.
3. REMOVE BLOWER MOTOR CONTROL RELAY
Remove the screw and blower motor control relay.
4. REMOVE AIR MIX SERVOMOTORS
Remove the 6 screws and both servomotors.
5. REMOVE AIR OUTLET SERVOMOTOR
Remove the 2 screws and servomotor.
6. REMOVE EXPANSION VALVE
(a) Pry out the packing.
HINT:
At the time of reassembly, please refer to the following item.
Do not reuse the packing.
(b) Using SST, remove the 2 bolts, then separate the expansion valve, tube connector and tube and ac-
cessory.
SST 07110±61050
Torque: 4.1N´m (42 kgf´cm, 36 in.´lbf)
HINT:
At the time of reassembly, please refer to the following item.
Lubricate 4 new O±rings with compressor oil and install them to the valve.
7. REMOVE EVAPORATOR TEMPERATURE SENSOR
(a) Disconnect the wire harness clamp.
(b) Using a screwdriver, pull out the sensor with bracket plate.
HINT:
Tape the screwdriver tip before use.
(c) Release the 2 claws and sensor from bracket plate.
8. REMOVE EVAPORATOR
(a) Using SST, remove the 2 bolts and tube and accessory.
SST 07110±61050
Torque: 4.1N´m (42 kgf´cm, 36 in.´lbf)
HINT:
At the time of reassembly, please refer to the following item.
Lubricate 2 new O±rings with compressor oil and install them to the tube.
(b) Remove the 4 screws and cover.
(c) Pull out the evaporator.
(d) Remove the plate from evaporator.
HINT:
At the time of reassembly, please refer to the following item.
If evaporator is replaced, add compressor oil to evaporator.
Add 40 cc (1.4fl.oz.)
Compressor oil: ND±OIL 8 or equivalent
9. REMOVE INSULATOR FROM HEATER CASE
10. REMOVE AIR DUCT
Remove the 4 screws and duct.
Page 27 of 1111
I01390
Condition: Insufficient cooling
I01392
Condition: Insufficient cooling
NOTE : These gauge indica-
tions are shown when the
refrigeration system has
been opened and the refrig-
erant charged without vacu-
um purging.
± AIR CONDITIONINGAIR CONDITIONING SYSTEM
AC±7
2692 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
(6) Refrigerant overcharged or insufficient cooling of
condenser
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
Pressure too high on both low
and high pressure sides
No air bubbles seen through the
sight glass even when the engine
rpm is lowered Unable to develop sufficient per-
formance due to excessive refrig-
eration system
Insufficient cooling of condenser Excessive refrigerant in
cycle " refrigerant over charged
Condenser cooling " condenser
fins clogged of condenser fan
faulty
(1) Clean condenser
(2) Check condenser fan motor
operation
(3) If (1) and (2) are in normal
state, check amount of refrigerant
Charge proper amount of refriger-
ant
(7) Air present in refrigeration system
Symptom seen in
refrigeration systemProbable causeDiagnosisRemedy
Pressure too high on both low
and high pressure sides
The low pressure piping hot to
touch
Bubbles seen in sight glass
Air entered in refrigeration system
Air present in refrigeration sys-
tem
Insufficient vacuum purging
(1) Check compressor oil to see if
it is dirty or insufficient
(2) Evacuate air and charge new
refrigerant
Page 35 of 1111
I02376
GS300:
3
I02375
GS400:
3
± AIR CONDITIONINGCOMPRESSOR AND MAGNETIC CLUTCH
AC±35
2720 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
5. MAKE THESE VISUAL CHECKS:
(a) Leakage of grease from the clutch bearing.
(b) Signs of oil on the pressure plate or rotor.
6. INSPECT MAGNETIC CLUTCH BEARING FOR NOISE
(a) Start engine.
(b) Check for abnormal noise from the compressor when the
A/C switch is OFF.
If abnormal noise is being emitted, replace the rotor of magnetic
clutch.
7. INSPECT MAGNETIC CLUTCH OPERATION
(a) Disconnect the connector.
(b) Connect the positive (+) lead from the battery to terminal
3 and the negative (±) lead to the body ground.
(c) Check that the magnetic clutch is energized.
If operation is not as specified, replace the magnetic clutch.
Page 44 of 1111
AC0WY±01
AC±44
± AIR CONDITIONINGCOMPRESSOR AND MAGNETIC CLUTCH
2729 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSTALLATION
1. GS400:
INSTALL COMPRESSOR
(a) Install the compressor with the 2 bolts temporarily.
(b) Install the compressor stay with the bolt and nut temporarily.
(c) Tighten the nut and 3 bolts.
Torque:
Bolt: 49 N´m (500 kgf´cm, 36 ft´lbf)
Nut: 29 N´m (300 kgf´cm, 22 ft´lbf)
(d) Connect the connector.
2. GS300:
INSTALL COMPRESSOR
(a) Install the compressor with the stud bolt.
Torque: 52 N´m (530 kgf´cm, 38 ft´lbf)
(b) Install the 3 bolts and nut.
Torque:
Bolt: 52 N´m (530 kgf´cm, 38 ft´lbf)
Nut: 26 N´m (265 kgf´cm, 19 ft´lbf)
(c) Connect the connector.
(d) Install the compressor bracket with the 2 bolts.
Torque: 52 N´m (530 kgf´cm, 38 ft´lbf)
(e) Install the PS pump bracket with the 2 bolts.
Torque: 52 N´m (530 kgf´cm, 38 ft´lbf)
3. GS300:
INSTALL 2 PS PUMP SET BOLTS
Torque: 58 N´m (590 kgf´cm, 43 ft´lbf)
4. GS 300:
CONNECT DISCHARGE AND SUCTION HOSES
Connect the both hoses with the 2 nut.
Torque: 10 N´m (100 kgf´cm, 7 ft´lbf)
NOTICE:
Hose should be connected immediately after the caps have been removed.
HINT:
Lubricate 2 new O±rings with compressor oil and install them to the hoses.
5. GS400:
CONNECT DISCHARGE HOSE
Connect the discharge hose with the nut.
Torque: 10 N´m (100 kgf´cm, 7 ft´lbf)
NOTICE:
Hose should be connected immediately after the cap have been removed.
HINT:
Lubricate a new O±ring with compressor oil and install them to the hose.
Page 45 of 1111
± AIR CONDITIONINGCOMPRESSOR AND MAGNETIC CLUTCH
AC±45
2730 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
6. GS400:
INSTALL SUCTION HOSE
Install the suction hose with the bolt and nut.
Torque: 10 N´m (100 kgf´cm, 7 ft´lbf)
NOTICE:
Hose should be connected immediately after the caps have been removed.
HINT:
Lubricate 2 new O±rings with compressor oil and install them to the hose.
7. INSTALL DRIVE BELT
(See page AC±16)
8. INSPECT DRIVE BELT TENSION
(See page AC±14)
9. INSTALL ENGINE UNDER COVER
10. CONNECT NEGATIVE (±) TERMINAL CABLE TO BATTER
11. EVACUATE AIR FROM REFRIGERATION SYSTEM AND CHARGE SYSTEM WITH REFRIGERANT
Specified amount: 600 ± 50 g (21.16 ± 1.76 oz.)
12. INSPECT FOR LEAKAGE OF REFRIGERANT
Using a gas leak detector, check for leakage of refrigerant.
If there is leakage, check the tightening torque at the joints.
13. INSPECT A/C OPERATION
Page 47 of 1111
AC22B±01
I09253
I09252I10327
O±Ring Liquid TubeDischarge Hose
N´m (kgf´cm, ft´lbf) : Specified torque
Non±reusable partAir Cleaner Assembly
Air Cleaner Duct Condenser
Bracket
Condenser
Dryer
Filter
Cap O±Ring
10 (100, 7)
10 (100, 7)
12.3 (125, 9)
Compressor oil ND±OIL 8 or equivalent
Radiator Upper Support
± AIR CONDITIONINGCONDENSER
AC±47
2732 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
COMPONENTS
