2012 TOYOTA PRIUS Coolant

426 4-3. Do-it-yourself maintenance
Radiator and condenserCheck the radiator and condenser and clear away any foreign
objects.
If either of the above parts is extr emely dirty or you are not sure of
their condition, have your vehicle inspected by your Toyota dealer.
NOTICE
■When adding coolant
Coolant is neither plain water nor stra ight 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 radiator or condenser as they may be hot and cause seri-
ous injuries, such as burns.

492
5-1. Essential information
If you think something is wrong
If you notice any of the following symptoms, your vehicle probably
needs adjustment or repair. Contact your Toyota dealer as soon as
possible.
■Visible symptoms
●Fluid leaks under the vehicle
(Water dripping from the air cond itioning after use is normal.)
● Flat-looking tires or uneven tire wear
● High engine coolant temperatur e warning light flashes or
comes on
■ Audible symptoms
●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
■ Operational symptoms
●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, s pongy feeling, pedal almost
touches the floor

494 5-2. Steps to take in an emergency
Stop the vehicle immediately.The following warning indicates the possibility of damage to the vehi-
cle that may lead to an accident. Immediately stop the vehicle in a
safe place and contact your Toyota dealer.
Warning lightWarning light/Details
Charging system warning light Indicates a malfunction in the vehicle’s charging system
High coolant temperature warning light Indicates that the coolant temperature is too high
Changes from a flashing to a solid light when the engine
coolant temperature increases.

5
When trouble arises
549
5-2. Steps to take in an emergency
If your vehicle overheats
Correction procedures■ If the high coolant temperature warning light flashes or comes
on
Stop the vehicle in a safe place and turn off the air condition-
ing system.
Check to see if steam is coming out from under the hood.
If you see steam: Stop the hybrid system. Carefully lift the hood after the
steam subsides and then restart the hybrid system.
If you do not see steam: Leave the hybrid system operating and carefully lift the
hood.
The following may indicate that your vehicle is overheating:
●The high coolant temperature warn ing light flashes or comes on:
The engine may be overheating.
● “HYBRID SYSTEM OVERHEAT” is shown on the multi-informa-
tion display:
The power control unit may be overheating.
Follow the correction procedure as described below.
STEP 1
STEP 2

550 5-2. Steps to take in an emergency
Check to see if the cooling fans are operating.
If the fans are operating: Wait until the high coolant temperature warning light goes
off and then stop the hybrid system.
If the fans are not operating: Stop the hybrid system immediately and call your Toyota
dealer.
After the hybrid system has
cooled down sufficiently, check
the engine coolant level and
inspect the cooling system for
leaks.
If necessary, add engine coolant
up to the “FULL” line.
Water can be used in an emer-
gency measure if engine coolant
is unavailable. (P. 566)
Have the vehicle checked at nearest Toyota dealer as soon as possi-
ble.
STEP 3
STEP 4
ITO52P130
STEP 5

5
When trouble arises
551
5-2. Steps to take in an emergency
■
If “HYBRID SYSTEM OVERHEAT” is shown on the multi-infor-
mation display
Stop the vehicle in a safe place and turn off the air condition-
ing system.
Leave the hybrid system operating and carefully lift the hood.
Check if the cooling fans are operating.
If the fans are operating: Wait until “HYBRID SYSTEM OVERHEAT” disappears and
then stop the hybrid system.
If the warning light does not turn off, call your Toyota dealer.
If the fans are not operating: Stop the hybrid system immediately and call your Toyota
dealer.
After the hybrid system has
cooled down, check the power
control unit coolant level and
inspect the cooling system for
leaks.
STEP 1
STEP 2
STEP 3
STEP 4

552 5-2. Steps to take in an emergency
If necessary, add power control
unit coolant up to the “F” line.
Water can be used in an emer-
gency measure if power control
unit coolant is unavailable.
(P. 566)
Have the vehicle checked at nearest Toyota dealer as soon as possi-
ble.
STEP 5
■ Overheating
The following symptoms may occur when your vehicle is overheating:
●Hybrid system output decrease
● Steam is coming from under the hood

5
When trouble arises
553
5-2. Steps to take in an emergency
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, caus-
ing serious injuries such as burns.
● Check that the indicator on the “POWER” switch and the “READY” indica-
tor are off.
● For vehicles with a hybrid system, there are times when the gasoline
engine automatically starts to run or the cooling fans suddenly start to
operate. Do not touch or approach the rotating parts of the fans, etc. 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 radia-
tor are hot.
Serious injury, 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 sys-
tem 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