Page 460 of 688
4606-3. Do-it-yourself maintenance
GS350_250_OM_OM30E16E_(EE)
CAUTION
■When the engine is hot
Do not remove the engine coolant reservoir cap or the coolant inlet cap. (→P. 6 2 5 )
The cooling system may be under pressure and may spray hot coolant if the cap is
removed, causing serious injuries, such as burns.
NOTICE
■When adding coolant
Coolant is neither plain water nor straight antifreeze. The correct mixture of water
and antifreeze must be used to provide proper lubrication, corrosion protection
and cooling. Be sure to read the antifreeze or coolant label.
■If you spill coolant
Be sure to wash it off with water to prevent it from damaging parts or paint.
GS350_250_OM_OM30E16E_(EE).book Page 460 Tuesday, July 8, 201 4 7:11 PM
Page 499 of 688
499 6-3. Do-it-yourself maintenance
6
Maintenance and care
GS350_250_OM_OM30E16E_(EE)
24ETCS10Multiport fuel injection system/sequential
multiport fuel injection system
25HORN10Horn
26R/B-B20EPS-B, TV
27P/ I - B N O.150Headlights, daytime running lights, EBS
28EPB30Pa r k in g b ra ke
29LUG J/B-B40Luggage compartment junction block
30FAN NO.180Electric cooling fans
31LH J/B ALT60Left-hand junction block
32H-LP CLN30Headlight cleaner
33FAN NO.240Electric cooling fans
34A/C COMP7. 5Air conditioning system
35FILTER10Condenser
FuseAmpereCircuit
GS350_250_OM_OM30E16E_(EE).book Page 499 Tuesday, July 8, 2014 7:11 PM
Page 501 of 688

501 6-3. Do-it-yourself maintenance
6
Maintenance and care
GS350_250_OM_OM30E16E_(EE)
16MPX-B10
Smart entry & start system, CAN gateway
ECU, electric tilt and telescopic steering col-
umn, power seats, head-up display, front
right-hand door ECU, gauges and meters,
steering sensor, yaw rate and G sensor, over-
head module, RR CTRL SW, clock, front left-
hand door ECU, power trunk lid, body ECU
17FILTER10Condenser
18A/C COMP7. 5Air conditioning system
19H-LP CLN30Headlight cleaner
20FAN NO.240Electric cooling fans
21LH J/B ALT60Left-hand junction block
22FAN NO.180Electric cooling fans
23P/ I - B N O.150H-LP HI RH, H-LP HI LH, DRL, emergency
brake signal
24EPB30Pa r k in g b ra ke
25LUG J/B-B40Luggage compartment junction block
26R/B-B20EPS-B, TV
27HORN10Horn
28ETCS10Multiport fuel injection system/sequential
multiport fuel injection system
29ALT-S7. 5Charging system
30ECU-B7. 5Smart entry & start system
31DCM7. 5DCM
32D/C C UT30DOME, MPX-B
33ABS NO.250VDIM
34ST30Starting system
35H-LP LO30Headlights, H-LP RLY
FuseAmpereCircuit
GS350_250_OM_OM30E16E_(EE).book Page 501 Tuesday, July 8, 2014 7:11 PM
Page 624 of 688

6247-2. Steps to take in an emergency
GS350_250_OM_OM30E16E_(EE)
CAUTION
■Battery precautions
The battery contains poisonous and corrosive acidic electrolyte, while related
parts contain lead and lead compounds. Observe the following precautions when
handling the battery:
●When working with the battery, always wear safety glasses and take care not to
allow any battery fluids (acid) to come into contact with skin, clothing or the vehi-
cle body.
●Do not lean over the battery.
●In the event that battery fluid comes into contact with the skin or eyes, immedi-
ately wash the affected area with water and seek medical attention.
Place a wet sponge or cloth over the affected area until medical attention can be
received.
●Always wash your hands after handling the battery support, terminals, and other
battery-related parts.
●Do not allow children near the battery.
NOTICE
■When handling jumper cables
When connecting the jumper cables, ensure that they do not become entangled in
the cooling fans or engine drive belt.
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Page 625 of 688

625
7
7-2. Steps to take in an emergency
When trouble arises
GS350_250_OM_OM30E16E_(EE)
If your vehicle overheats
Stop the vehicle in a safe place and turn off the air conditioning system,
and then stop the engine.
If you see steam:
Carefully lift the hood after the steam subsides.
If you do not see steam:
Carefully lift the hood.
After the engine has cooled down sufficiently, inspect the hoses and
radiator core (radiator) for any leaks.
Radiator
Cooling fans
If a large amount of coolant leaks,
immediately contact any autho-
rized Lexus dealer or repairer, or
another duly qualified and
equipped professional.
The following may indicate that your vehicle is overheating.
●The needle of the engine coolant temperature gauge ( →P. 99)
enters the red zone or a loss of engine power is experienced. (For
example, the vehicle speed does not increase.)
●Steam is coming from under the hood.
Correction procedures
1
2
3
1
2
GS350_250_OM_OM30E16E_(EE).book Page 625 Tuesday, July 8, 201 4 7:11 PM
Page 626 of 688

6267-2. Steps to take in an emergency
GS350_250_OM_OM30E16E_(EE)
The coolant level is satisfactory if it is between the “FULL” and “LOW”
lines on the reservoir.Reservoir“FULL”
“LOW”
Coolant inlet cap
Add coolant if necessary.
Water can be used in an emergency if
coolant is unavailable.
Start the engine and turn the air co nditioning system on to check that
the radiator cooling fans operate and to check for coolant leaks from
the radiator or hoses.
The fans operate when the air conditioning system is turned on immediately after
a cold start. Confirm that the fans are operating by checking the fan sound and air
flow. If it is difficult to check these, turn the air conditioning system on and off
repeatedly. (The fans may not operate in freezing temperatures.)
If the fans are not operating:
Stop the engine immediately and contact any authorized Lexus dealer
or repairer, or another duly qualified and equipped professional.
If the fans are operating:
Have the vehicle inspected at the nearest any authorized Lexus dealer
or repairer, or another duly qualified and equipped professional.
4
1
2
3
4
5
6
7
GS350_250_OM_OM30E16E_(EE).book Page 626 Tuesday, July 8, 201 4 7:11 PM
Page 627 of 688

6277-2. Steps to take in an emergency
7
When trouble arises
GS350_250_OM_OM30E16E_(EE)
CAUTION
■When inspecting under the hood of your vehicle
Observe the following precautions.
Failure to do so may result in serious injury such as burns.
●If steam is seen coming from under the hood, do not open the hood until the
steam has subsided. The engine compartment may be very hot.
●Keep hands and clothing (especially a tie, a scarf or a muffler) away from the fans
and belts. Failure to do so may cause the hands or clothing to be caught, resulting
in serious injury.
NOTICE
■When adding engine coolant
Add coolant slowly after the engine has cooled down sufficiently. Adding cool
coolant to a hot engine too quickly can cause damage to the engine.
■To prevent damage to the cooling system
Observe the following precautions:
●Avoid contaminating the coolant with foreign matter (such as sand or dust etc.).
●Do not use any coolant additives.
●Do not loosen the coolant inlet cap or the
coolant reservoir cap while the engine and
radiator are hot.
High temperature steam or coolant could
spray out.
GS350_250_OM_OM30E16E_(EE).book Page 627 Tuesday, July 8, 2014 7:11 PM
Page 642 of 688
6428-1. Specifications
GS350_250_OM_OM30E16E_(EE)
Cooling system
GS250
GS350Left-hand drive
vehiclesRight-hand
drive vehicles
Capacity10.9 L (11.5 qt.,
9.6 I m p . q t . )11.0 L (11.6 qt.,
9.7 I m p.q t.)9.7 L ( 1 0. 3 q t . ,
8.5 Imp.qt.)
Coolant typeUse either of the following:• “Toyota Super Long Life Coolant”
• Similar high-quality ethylene glycol-based non-silicate, non-amine, non-nitrite, and non-borate
coolant with long-life hybrid organic acid tech-
nology
Do not use plain water alone.
Ignition system
Spark plug
Make
GapDENSO FK20HBR11
1.1 mm (0.043 in.)
NOTICE
■Iridium-tipped spark plugs
Use only iridium-tipped spark plugs. Do not adjust the spark plug gap.
GS350_250_OM_OM30E16E_(EE).book Page 642 Tuesday, July 8, 201 4 7:11 PM