Page 643 of 860

GS450h_U (OM30D01U)
6436-3. Do-it-yourself maintenance
6
Maintenance and care
■Coolant selection
Only use “Toyota Super Long Life Coolant” or a similar high quality ethylene glycol
based non-silicate, non-amine, non-nitrite, and non-borate coolant with long-life
hybrid organic acid technology.
U.S.A.:
“Toyota Super Long Life Coolant” is a mixture of 50% coolant and 50% deionized
water. (Minimum temperature: -31 F [-35C])
Canada:
“Toyota Super Long Life Coolant” is a mixture of 55% coolant and 45% deionized
water. (Minimum temperature: -44 F [-42C])
For more details about coolant, contact your Lexus dealer.
■If the coolant level drops within a short time of replenishing
Visually check the radiator, hoses, engine/power control unit coolant reservoir caps,
drain cock and water pump.
If you cannot find a leak, have your Lexus dealer 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 un it coolant reservoir caps or the radia-
tor cap.( P. 777)
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 710 of 860
710
GS450h_U (OM30D01U)
7-2. Steps to take in an emergency
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 probably
needs adjustment or repair. Contact your Lexus dealer as soon as pos-
sible.
Visible symptoms
Audible symptoms
Operational symptoms
Page 774 of 860

774
GS450h_U (OM30D01U)
7-2. Steps to take in an emergency
If your vehicle overheats
●The needle of the engine coolant temperature gauge enters the red
zone:
The engine may be overheating.
●“Hybrid System Overheat” is shown on the multi-information display:
The power control unit may be overheating.
■If the needle of the engine coolant temperature gauge enters the red
zone
Stop the vehicle in a safe place an d turn off the air conditioning sys-
tem.
Check to see if steam is coming out from the engine area.
If you see steam:
Stop the hybrid system. Carefull y lift the hood after the steam sub-
sides and then restart the hybrid system.
If you do not see steam:
Leave the hybrid system operating and carefully lift the hood.
Check to see if the cooling fans are operating.
If the fans are operating:
Wait until the engine coolant temperature ga uge begins to fall and
then stop the hybrid system.
If the fans are not operating:
Stop the hybrid system immediately and call your Lexus dealer.
The following may indicate that your vehicle is overheating:
Correction procedures
1
2
3
Page 775 of 860

7757-2. Steps to take in an emergency
GS450h_U (OM30D01U)
7
When trouble arises
After the hybrid system has
cooled down sufficiently,
check the engine coolant level
and inspect the cooling sys-
tem for leaks.
If the engine compartment cover
needs to be removed: P. 6 3 8
Add engine coolant if neces-
sary.
Water can be used in an emer-
gency if engine coolant is unavail-
able. ( P. 7 8 7 )
Have the vehicle inspected at the nearest Lexus dealer as soon as pos-
sible.
■If “Hybrid System Overheat” is shown on the multi-information dis-
play
Stop the vehicle in a safe place an d turn off the air conditioning sys-
tem.
Leave the hybrid system operating and carefully lift the hood.
Check if the cooling fans are operating.
If the fans are operating:
Wait until the “Hybrid System Overheat” message disappears and
then stop the hybrid system.
If the message does not disapp ear, call your Lexus dealer.
If the fans are not operating:
Stop the hybrid system immediately and call your Lexus dealer.
4
5
1
2
3
Page 776 of 860
7767-2. Steps to take in an emergency
GS450h_U (OM30D01U)After the hybrid system has
cooled down, check the power
control unit coolant level and
inspect the cooling system for
leaks.
If the engine compartment cover
needs to be removed:
P. 6 3 8
Add power control unit cool-
ant if necessary.
Water can be used in an emer-
gency if power control unit coolant
is unavailable. ( P. 7 8 7 )
Have the vehicle inspected at the nearest Lexus dealer as soon as pos-
sible.
■Overheating
If you observe the following, your vehicle may be overheating:
●The engine coolant temperature gauge enters the red zone or a loss of power is
experienced.
●“Hybrid System Overheat” is shown on the multi-information display.
●Steam comes out from under the hood.
4
5
Page 777 of 860

7777-2. Steps to take in an emergency
GS450h_U (OM30D01U)
7
When trouble arises
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 away from the fans , etc. while the hybrid system is oper-
ating.
●For vehicles with a hybrid system, there are times when the gasoline engine auto-
matically starts to run or the cooling fans suddenly start to operate. Do not touch
or approach the rotating parts of the belt or fans. Doing so may lead to fingers,
clothes or tools getting caught, resulting in injury.
NOTICE
■When adding engine/power control unit coolant
Add coolant slowly after the hybrid syst em has cooled down sufficiently. Adding
cool coolant to a hot hybrid system too quickly can cause da mage 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 commercially available coolant additives.
●Do not loosen the radiator cap or the cool-
ant reservoir caps while the hybrid system
and radiator are hot.
High temperature steam or coolant could
spray out.
Page 787 of 860
GS450h_U (OM30D01U)
7878-1. Specifications
8
Vehicle specifications
Cooling system
Capacity
Gasoline
engine9.9 qt. (9.4 L, 8.3 Imp.qt.)
Pow e r
control unit3.3 qt. (3.1 L, 2.7 Imp.qt.)
Coolant type
Use 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
MakeDENSO FK20HBR8
Gap0.031 in. (0.8 mm)
NOTICE
■Iridium-tipped spark plugs
Use only iridium-tipped spark plugs. Do not adjust the spark plug gap.
Page 802 of 860

802
GS450h_U (OM30D01U)
8-1. Specifications
Glossary of tire terminology
Tire related termMeaning
Cold tire inflation pres-
sureTire pressure when the vehicle has been parked for
three hours or more, or has not been driven more
than 1 mile or 1.5 km under that condition
Maximum inflation pres-
sureThe maximum cold inflated pressure to which a tire
may be inflated, shown on the sidewall of the tire
Recommended inflation
pressureCold tire inflation pressure recommended by a man-
ufacturer
Accessory weight
The combined weight (in excess of those standard
items which may be replaced) of hybrid transmission,
power steering, power brakes, power windows,
power seats, radio and heater, to the extent that these
items are available as factory-installed equipment
(whether installed or not)
Curb weight
The weight of a motor vehicle with standard equip-
ment, including the maximum capacity of fuel, oil and
coolant, and if so equipped, air conditioning and
additional weight optional engine
Maximum loaded vehicle
weight
The sum of:
(a) Curb weight
(b) Accessory weight
(c) Vehicle capacity weight
(d) Production options weight
Normal occupant weight150 lb. (68 kg) times the number of occupants speci-
fied in the second column of Table 1
* that follows
Occupant distributionDistribution of occupants in a vehicle as specified in
the third column of Table 1
* below
Production options weight
The combined weight of installed regular production
options weighing over 5 lb. (2.3 kg) in excess of the
standard items which they replace, not previously
considered in curb weight or accessory weight,
including heavy duty brakes, ride levelers, roof rack,
heavy duty 12-volt battery, and special trim
RimA metal support for a tire or a tire and tube assembly
upon which the tire beads are seated