Page 588 of 792
588
PRIUS PRIME_OM_OM47C77U_(U)
7-3. Do-it-yourself maintenance
Engine compartment
Engine coolant reservoir ( P. 592)
Fuse boxes ( P. 638)
Engine oil level dipstick ( P. 589)
Engine oil filler cap ( P. 590)
Brake fluid reservoir ( P. 598) Washer fluid tank (
P. 600)
12-volt battery ( P. 595)
Power control unit coolant
reservoir ( P. 592)
Radiator ( P. 594)
Condenser ( P. 594)
Electric cooling fans1
2
3
4
5
6
7
8
9
10
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Page 592 of 792
592
PRIUS PRIME_OM_OM47C77U_(U)
7-3. Do-it-yourself maintenance
The coolant level is satisfactory if it is between the “FULL” a nd “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. 709)
■
Power control unit 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. 709)
Coolant
1
2
3
1
2
3
Page 593 of 792

PRIUS PRIME_OM_OM47C77U_(U)
5937-3. Do-it-yourself maintenance
7
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-bora te coolant with
long-life hybrid organic acid technology.
U.S.A.:
“Toyota Super Long Life Coolant” is a mixture of 50% coolant and 50% deion-
ized water. (Minimum temperature: -31 F [-35 C])
Canada:
“Toyota Super Long Life Coolant” is a mixture of 55% coolant and 45% deion-
ized water. (Minimum temperature: -44 F [-42 C])
For more details about coolant, contact your Toyota dealer.
■ If the coolant level drops within a short time of replenishing
Visually check the radiator, hoses, engine/power control unit c oolant reservoir
caps, drain cock and water pump.
If you cannot find a leak, have your Toyota dealer test the cap and check for
leaks in the cooling system.
WARNING
■ When the hybrid system is hot
Do not remove the engine/power control unit coolant reservoir c aps.
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 cor rect 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 p arts or paint.
Page 710 of 792

7108-2. Steps to take in an emergency
PRIUS PRIME_OM_OM47C77U_(U)
The coolant level is satisfactory if it is between the “FULL” and
“LOW” lines on the reservoir.
Reservoir
“FULL” line
“LOW” line
Add coolant if necessary.
Water can be used in an emer-
gency if 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 t he radiator or hoses.
The fans operate when the temperature setting is adjusted to “LO” and
“A/C” switch (
*1 • *2) is turned on immediately 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 “A/C” switch
(
*1 • *2) on and off repeatedly. (The fans may not
operate in freezing temperatures.)
*1: Vehicles with 7-inch display
*2: Vehicles with 11.6-inch display
If the fans are not operating:
Stop the hybrid system immediately and contact your Toyota
dealer.
If the fans are operating:
Have the vehicle inspected at the neare st Toyota dealer.
4
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2
3
5
6
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Page 711 of 792
7118-2. Steps to take in an emergency
PRIUS PRIME_OM_OM47C77U_(U)
8
When trouble arises
■If “Hybrid System Overheated” is shown on the multi-informa-
tion displayStop 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 (radiat or) for any leaks.
Radiator
Cooling fans
If a large amount of coolant
leaks, immediately contact
your Toyota dealer.
The coolant level is satisfactory if it is between the “FULL” a nd
“LOW” lines on the reservoir.
Reservoir
“FULL” line
“LOW” line
Add coolant if necessary.
Water can be used in an emer-
gency if coolant is unavailable.
If water was added in an emer-
gency, have the vehicle inspected
at your Toyota dealer as soon as
possible.
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3
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2
4
1
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Page 712 of 792

7128-2. Steps to take in an emergency
PRIUS PRIME_OM_OM47C77U_(U)
After stopping the hybrid system and waiting for 5 minutes or
more, start the hybrid system again and check if “Hybrid System
Overheated” is shown on the multi-information display.
If the message d oes not disappear:
Stop the hybrid system and contact your Toyota dealer.
If the message is not displayed:
The hybrid system temperature has dropped and the vehicle may
be driven normally.
However, if the message appears again frequently, contact your Toyota
dealer.
WARNING
■ To prevent an accident or injury 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 ho od until
the steam has subsided. The engine compartment may be very hot.
● After the hybrid system has been turned off, check that the “Ac cessory”,
“Ignition ON” or mileage display ( P. 210) on the main display and the
“READY” indicator are off.
When the hybrid system is operating, the gasoline engine may au tomati-
cally start, or the cooling fans 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 muffler)
getting caught, resulting in serious injury.
● Do not loosen the coolant reservoir caps while the hybrid syste m and radi-
ator are hot.
High temperature steam or coolant could spray out.
6