2012 Lexus HS250h coolant reservoir

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4-3. Do-it-yourself maintenance
4
Maintenance and care
HS250h_U_75050U
Engine compartment
Engine coolant reservoir (→P. 4 4 2 )
Engine oil filler cap (→P. 4 3 9 )
Engine oil level dipstick (→P. 4 3 9 )
Power control unit coolant
reservoir ( →P. 4 4 2 )
Brake fluid reservoir (→P. 445)Fuse box ( →P. 4 6 9 )
Engine coolant radiator (→P. 444)
Power control unit coolant
radiator (→ P. 444)
Condenser ( →P. 444)
Electric cooling fans
Washer fluid tank (→P. 4 4 6 )

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4-3. Do-it-yourself maintenance
HS250h_U_75050U
CoolantThe 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. 5 6 4 )

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4-3. Do-it-yourself maintenance
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Maintenance and care
HS250h_U_75050UPower control unit coolant reservoir
Reser voir cap
“FULL” line
“LOW” line
If the level is on or below the
“LOW” line, add coolant up to the
“FULL” line. (→P. 5 6 4 )
■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 [-35 °C])
Canada: “Toyota Super Long Life Coolant” is a mixture of 55% coolant and 45% deionized water. (Minimum temperature: -44 °F [-42 °C])
For more details about coolant, contact your Lexus dealer.
■If the coolant level drops within a short time of replenishing
Visually check the radiators, 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 systems.

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4-3. Do-it-yourself maintenance
HS250h_U_75050U
Radiator and condenserCheck the radiator and condenser and clear away any foreign objects.
If either of the above parts is extremely dirty or you are not sure of their
condition, have your vehicle inspected by your Lexus dealer.
CAUTION
■When the hybrid system is hot
Do not remove the engine/power control unit coolant reservoir caps.
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.
CAUTION
■When the hybrid system is hot
Do not touch the radiators or condenser as they may be hot and cause serious inju-
ries, such as burns.

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5-2. Steps to take in an emergency
HS250h_U_75050UCheck that the coolant level of the
power control unit is between the
“FULL” and “LOW” lines of the
reservoir tank.
“FULL” line
“LOW” line
If the coolant level of the power
control unit is insufficient, add
more coolant.
If power control unit coolant is
unavailable, water can be used as
an emergency substitute.
Restart the hybrid system (depress and hold the brake pedal, and
press the “POWER” switch once). Check that the “HYBRID
SYSTEM OVERHEAT” message has gone off.
If the warning message remains on, stop the hybrid system and
contact your Lexus dealer.
Have the vehicle inspected at the nearest Lexus dealer as soon as possi-
ble.
■Overheating
The following symptoms may occur when your vehicle is overheating:
●The high engine coolant temperature warning light comes on or flashes, or the
hybrid system output decreases.
●Steam comes out from the engine area.
●“HYBRID SYSTEM OVERHEAT” is displayed on the multi-information display.

5
When trouble arises
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5-2. Steps to take in an emergency
HS250h_U_75050U
CAUTION
■To prevent an accident or injury when inspecting under the hood of your vehicle
●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, causing serious
injuries such as burns.
●Check that the indicator on the “POWER” switch and the READY indicator are
off.
●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.
●Do not loosen the coolant reservoir cap while the hybrid system and radiator are
hot.
Serious injuries, such as burns, may result from hot coolant and steam released
under pressure.
NOTICE
■When adding engine/power control unit coolant
Wait until the hybrid system has cooled down before adding engine/power control
unit coolant.
When adding coolant, do so slowly. 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 commercially available coolant additives