2013 Lexus GS300h Owner's Manual

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
GS300hGS450h
4
1
2
3
4
GS300hGS450h

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
GS300hGS450h
6
7

9207-2. Steps to take in an emergency
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If “Hybrid System Overheat” is shown on the multi-information
display
Stop the vehicle in a safe place.
Stop the hybrid system and carefully lift the hood.
After the hybrid system has cooled down, inspect the hoses
and radiator core (radiator) for any 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 “F”/
“FULL” and “L”/“LOW” lines on the reservoir.
Reservoir
“F”/“FULL”
“L”/“LOW”
1
2
3
1
2
GS300hGS450h
4
1
2
3
GS300hGS450h

9217-2. Steps to take in an emergency
7
When trouble arises
GS450h_300h_OM_OM30D53E_(EE)

9227-2. Steps to take in an emergency
GS450h_300h_OM_OM30D53E_(EE)
Add coolant if necessary.
Water can be used in an emergency if power control unit coolant is
unavailable.
Start the hybrid system and check for the multi-information
display.
If the message does not disappear:
Stop the hybrid system and contact your Lexus dealer.
If the message is not displayed:
Have the vehicle inspected at the nearest Lexus dealer.
5
GS300hGS450h
6

923
7 7-2. Steps to take in an emergency
When trouble arises
GS450h_300h_OM_OM30D53E_(EE)
When adding coolant
Add coolant in accordance with the following procedure.
Remove caps A and B.
Add coolant through the inlet of cap A up to the B-line, and then install cap
A.
Add coolant through the inlet of cap B until it is full, and then install cap B.
GS300h only: When installing cap B, apply coolant to the O-ring on the
end of cap B.
Cap A
Cap B
B-line (Target fill line)
1
2
3
GS300h GS450h
1
2
3

9247-2. Steps to take in an emergency
GS450h_300h_OM_OM30D53E_(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.
After the hybrid system has been turned off, check that the indicator on
the power switch and the “READY” indicator are off.
When the hybrid system is operating, the gasoline engine may automati-
cally start, or the cooling fan may suddenly operate even if the gasoline
engine stops. Do not touch or approach rotating parts such as the fan,
which may lead to fingers or clothing (especially a tie, a scarf or a muf-
fler) getting caught, resulting in serious injury.
Do not loosen the coolant inlet cap or
the coolant reservoir caps while the
hybrid system and radiator are hot.
High temperature steam or coolant
could spray out.

9257-2. Steps to take in an emergency
7
When trouble arises
GS450h_300h_OM_OM30D53E_(EE)
NOTICE
When adding engine/power control unit coolant
Add coolant slowly after the hybrid system has cooled down sufficiently.
Adding cool coolant to a hot hybrid system too quickly can cause damage
to the hybrid system.
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.