2021 TOYOTA PRIUS PLUG-IN HYBRID radiator

6317-3. Do-it-yourself maintenance
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
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Maintenance and care
Do-it-yourself service precautions
If you perform maintenance by yourself, be sure to follow the
correct procedure as given in these sections.
ItemsParts and tools
12-volt battery
condition
(P. 644)• Warm water • Baking soda • Grease
• Conventional wrench (for terminal clamp bolts)
• Distilled water
Engine/power
control unit
coolant level
(P. 641)• “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
“Toyota Super Long Life Coolant” is pre-mixed with
50% coolant and 50% deionized water.
• Funnel (used only for adding coolant)
Engine oil level
(P. 638)• “Toyota Genuine Motor Oil” or equivalent
• Rag or paper towel
• Funnel (used only for adding engine oil)
Fuses (P. 6 9 1 )• Fuse with same amperage rating as original
Hybrid battery
(traction battery)
air intake vent
(P. 623)
• Vacuum cleaner, etc.
• Flathead screwdriver
Light bulbs
(P. 695)
• Bulb with same number and wattage rating as origi-
nal
• Flathead screwdriver
• Wrench
Radiator and
condenser
(P. 643)

Tire inflation
pressure
(P. 665)• Tire pressure gauge
• Compressed air source
Washer fluid
(P. 648)• Water or washer fluid containing antifreeze (for win-
ter use)
• Funnel (used only for adding water or washer fluid)

6327-3. Do-it-yourself maintenance
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
WARNING
The engine compartment contains many mechanisms and fluids that may
move suddenly, become hot, or become el ectrically energized. To avoid death
or serious injury, observe the following precautions.
■ When working on the engine compartment
● Make sure that the “Accessory”, “Ignition ON” or mileage display (P. 223)
on the main display and the “READY” indicator are both off.
● Keep hands, clothing and tools away from the moving fan.
● Be careful not to touch the engine, power control unit, radiator, exhaust
manifold, etc. right after driving as they may be hot. Oil and other fluids
may also be hot.
● Do not leave anything that may burn easily, such as paper and rags, in the
engine compartment.
● Do not smoke, cause sparks or expose an open flame to fuel. Fuel fumes
are flammable.
● Be extremely cautious when working on the 12-volt battery. It contains poi-
sonous and corrosive sulfuric acid.
● Take care because brake fluid can harm your hands or eyes and damage
painted surfaces. If fluid gets on your hands or in your eyes, flush the
affected area with clean water immediately. If you still experience discom-
fort, consult a doctor.
■ When working near the electric cooling fans or radiator grille
Be sure the power switch is off.
With the power switch in ON mode, the electric cooling fans may automati-
cally start to run if the air conditioning is on and/or the coolant temperature
is high. ( P. 643)
■ Safety glasses
Wear safety glasses to prevent flying or falling material, fluid spray, etc.
from getting in your eyes.

6377-3. Do-it-yourself maintenance
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
7
Maintenance and care
Engine compartment
IO73PH114
Engine coolant reservoir
( P. 641)
Fuse boxes ( P. 691)
Engine oil level dipstick
( P. 638)
Engine oil filler cap ( P. 639)
Washer fluid tank ( P. 648)
12-volt battery ( P. 644)
Power control unit coolant
reservoir ( P. 641)
Radiator ( P. 643)
Condenser ( P. 643)
Electric cooling fans
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6427-3. Do-it-yourself maintenance
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
■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.
“Toyota Super Long Life Coolant” is a mixture of 50% coolant and 50% deion-
ized water. (Minimum temperature: -35 C [-31F])
For more details about coolant, contact any authorized Toyota retailer or
Toyota authorized repairer, or any reliable repairer.
■ 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 any authorized Toyota retailer or Toyota autho-
rized repairer, or any reliable repairer, 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 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.

6437-3. Do-it-yourself maintenance
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
7
Maintenance and care
Check 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 any authorized Toyota
retailer or Toyota authorized repairer, or any reliable repairer.
Radiator and condenser
WARNING
■ 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.
■ When the electric cooling fans are operating
Do not touch the engine compartment.
With the power switch in ON mode, the electric cooling fans may automati-
cally start to run if the air conditioning is on and/or the coolant temperature
is high. Be sure the power switch is off when working near the electric cool-
ing fans or radiator grille.

7618-2. Steps to take in an emergency
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
8
When trouble arises
If your vehicle overheats
■If the high coolant temperature warning light comes on or
flashes
Stop the vehicle in a safe place and turn off the air conditioning
system, and then stop the hybrid system.
If you see steam:
Carefully lift the hood after the steam subsides.
If you do not see steam:
Carefully lift the hood.
After the hybrid system has cooled down sufficiently, inspect the
hoses and radiator core (radiator) for any leaks.
Radiator
Cooling fans
If a large amount of coolant
leaks, immediately contact
any authorized Toyota retailer
or Toyota authorized repairer,
or any reliable repairer.
The following may indicate that your vehicle is overheating.
● The high coolant temperature warning light (P. 716) comes on
or flashes, or a loss of hybrid system power is experienced. (For
example, the vehicle speed does not increase.)
● “Hybrid System Overheated” is shown on the multi-information
display.
● Steam comes out from under the hood.
Correction procedures
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7628-2. Steps to take in an emergency
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
The coolant level is satisfactory if it is between the “MAX” and
“MIN” lines on the reservoir.
Reservoir
“MAX” line
“MIN” 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 the radiator or hoses.
The fans operate when the temperature setting is adjusted to “LO” and
“A/C” switch ( ) is turned on immediately after a cold start. Con-
firm 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 ( ) 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 any authorized
Toyota retailer or Toyota authorized repairer, or any reliable
repairer.
If the fans are operating:
Have the vehicle inspected at the nearest any authorized Toyota
retailer or Toyota authorized repairer, or any reliable repairer.
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7638-2. Steps to take in an emergency
Prius Plug-in Hybrid_OM_OM47D72E_(EE)
8
When trouble arises
■If “Hybrid System Overheated” is shown on the multi-informa-
tion 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
any authorized Toyota retailer
or Toyota authorized repairer,
or any reliable repairer.
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.
If water was added in an emer-
gency, have the vehicle
inspected at any authorized
Toyota retailer or Toyota autho-
rized repairer, or any reliable
repairer as soon as possible.
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