Page 763 of 1014
739 6-3. Do-it-yourself maintenance
6
Maintenance and care
GS450h_300h_OM_OM30D53E_(EE)
GS450h
12-volt battery
P. 7 4 9
Engine oil level dipstick
(P. 741)
Engine coolant reservoir
(P. 744)
Engine oil filler cap (P.
742)
Power control unit coolant
reservoir (P. 745)Fuse box (P. 782)
Washer fluid tank (P. 748)
Electric cooling fans
Condenser (P. 747)
Radiator (P. 747)1
2
3
4
5
6
7
8
9
Page 768 of 1014
7446-3. Do-it-yourself maintenance
GS450h_300h_OM_OM30D53E_(EE)
The coolant level is satisfactory if it is between the “FULL” and
“LOW” lines on the reservoir when the hybrid system is cold.
Engine coolant reservoir
Reservoir cap
“FULL” line
“LOW” line
If the level is on or below the “LOW” line, add coolant up to the
“FULL” line. (P. 915)
Coolant
GS300hGS450h
1
2
3
Page 769 of 1014
745 6-3. Do-it-yourself maintenance
6
Maintenance and care
GS450h_300h_OM_OM30D53E_(EE)
Power control unit coolant reservoir
GS300hGS450h
Reservoir cap
“F” line
“L” lineReservoir cap
“FULL” line
“LOW” line
If the level is on or below the
“L” line, add coolant up to the
“F” line. (P. 9 1 5 )If the level is on or below the
“LOW” line, add coolant up to
the “FULL” line. (P. 915)
1
2
3
1
2
3
Page 770 of 1014

7466-3. Do-it-yourself maintenance
GS450h_300h_OM_OM30D53E_(EE)
Coolant selection
Only use “Toyota Super Long Life Coolant” or a similar high quality eth-
ylene glycol based non-silicate, non-amine, non-nitrite, and non-borate cool-
ant with long-life hybrid organic acid technology.
“Toyota Super Long Life Coolant” is a mixture of 50% coolant and 50%
deionized water. (Minimum temperature: -35C [-31F])
For more details about coolant, contact any authorized Lexus dealer or
repairer, or another duly qualified and equipped professional.
If the coolant level drops within a short time of replenishing
Visually check the radiator, hoses, engine/power control unit coolant reser-
voir caps, drain cock and water pump.
If you cannot find a leak, have any authorized Lexus dealer or repairer, or
another duly qualified and equipped professional, test the cap and check for
leaks in the cooling system.
CAUTION
When the hybrid system is hot
Do not remove the engine/power control unit coolant reservoir caps or the
coolant inlet cap. (P. 9 2 1 )
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.
Page 856 of 1014

829
7 7-2. Steps to take in an emergency
When trouble arises
GS450h_300h_OM_OM30D53E_(EE)
If you think something is wrong
Fluid leaks under the vehicle.
(Water dripping from the air conditioning after use is normal.)
Flat-looking tires or uneven tire wear
Engine coolant temperature gauge needle continually points
higher than normal.
Changes in exhaust sound
Excessive tire squeal when cornering
Strange noises related to the suspension system
Pinging or other noises related to the hybrid system
Engine missing, stumbling or running roughly
Appreciable loss of power
Vehicle pulls heavily to one side when braking
Vehicle pulls heavily to one side when driving on a level road
Loss of brake effectiveness, spongy feeling, pedal almost
touches the floor
If you notice any of the following symptoms, your vehicle proba-
bly needs adjustment or repair. Contact any authorized Lexus
dealer or repairer, or another duly qualified and equipped profes-
sional as soon as possible.
Visible symptoms
Audible symptoms
Operational symptoms
Page 944 of 1014
9177-2. Steps to take in an emergency
7
When trouble arises
GS450h_300h_OM_OM30D53E_(EE)
If your vehicle overheats
If the needle of the engine coolant temperature gauge enters the
red zone
Stop the vehicle in a safe place and turn off the air condition-
ing system, and then stop the hybrid system.
If you see steam:
Carefully lift the hood after the steam subsides.
If you do not see steam:
Carefully lift the hood.
The following may indicate that your vehicle is overheating.
The needle of the engine coolant temperature gauge (P. 109)
enters the red zone or a loss of hybrid system power is experi-
enced. (For example, the vehicle speed does not increase.)
“Hybrid System Overheat” (P. 856) is shown on the multi-
information display.
Steam comes out from under the hood.
Correction procedures
1
2
Page 945 of 1014
9187-2. Steps to take in an emergency
GS450h_300h_OM_OM30D53E_(EE)
After the hybrid system has cooled down sufficiently, inspect
the hoses and cooling system for leaks.
Radiator
Cooling fans
If a large amount of coolant leaks, immediately contact your Lexus
dealer.
The coolant level is satisfactory if it is between the “FULL”
and “LOW” lines on the reservoir.
Reservoir
“FULL”
“LOW”
Coolant inlet cap
3
1
2
GS300hGS450h
4
1
2
3
4
GS300hGS450h
Page 946 of 1014
9197-2. Steps to take in an emergency
7
When trouble arises
GS450h_300h_OM_OM30D53E_(EE)
Add coolant if necessary. (P. 923)
Water can be used in an emergency if engine coolant is unavailable.
Start the hybrid system and turn the air conditioning 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 immedi-
ately 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 hybrid system immediately and contact your Lexus
dealer.
If the fans are operating:
Have the vehicle inspected at the nearest Lexus dealer.
5
GS300hGS450h
6
7