2020 TOYOTA MIRAI coolant reservoir

3697-3. Do-it-yourself maintenance
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Maintenance and care
Motor compartment
Washer fluid tank (P. 373)
Brake fluid reservoir ( P. 372)
Inverter coolant reservoir ( P. 370)
Fuse box ( P. 402)
Fuel cell stack coolant radiator
( P. 371) Inverter coolant radiator
( P. 371)
Condenser ( P. 371)
Electric cooling fans
Fuel cell stack coolant reser-
voir ( P. 370)
Fuel cell stack coolant sub
radiator ( P. 371)

3707-3. Do-it-yourself maintenance
MIRAI_OM_USA_OM62073U
The coolant level is satisfactory if it is between the “FULL” a nd “LOW”
lines on the reservoir when the fuel cell system is cold.
“FULL” line
“LOW” line
If the level is on or below the
“LOW” line, contact your Toyota
dealer.
The coolant level is satisfact ory if it is between the “FULL” a nd “LOW”
lines on the reservoir when the fuel cell system is cold.
Inverter coolan t reservoir cap
“FULL” line
“LOW” line
If the level is on or below the
“LOW” line, add coolant up to the
“FULL” line.
■ Inverter 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.
For the U.S.A.: “Toyota Super Long Life Coolant” is a mixture o f 50% coolant and
50% deionized water. (Minimum temperature: -31
F [-35C])
For 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 inverter coolant, contact your Toyota dealer.
Fuel cell stack coolant
NOTICE
■ Fuel cell stack coolant
An exclusive coolant for the fuel cell system is filled in the fuel cell stack
coolant reservoir. Do not use any substitute. It may damage you r vehicle.
Inverter coolant

3717-3. Do-it-yourself maintenance
MIRAI_OM_USA_OM62073U
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Maintenance and care
■If the inverter coolant level drops within a short time of repl enishing
Visually check the radiators, hoses, inverter coolant reservoir cap, 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.
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 vehic le inspected by your Toyota dea ler.
WARNING
■When the fuel cell system is hot
Do not remove the 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 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.
Radiator and condenser
WARNING
■When the fuel cell system is hot
Do not touch the radiator or condenser as they may be hot and c ause seri-
ous injuries, such as burns.

4578-2. Steps to take in an emergency
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When trouble arises
If your vehicle overheats
The following may indicate that your vehicle is overheating.
● The high coolant temperature warning light ( P. 418) comes on
or flashes, or a loss of fuel ce ll system power is experienced. (For
example, the vehicle s peed does not increase.)
● “FC System Overheat Output Power is Limited” ( P. 426) is dis-
played on the multi-in formation display
● Steam comes out from under the hood.
Label
Fuel cell stack coolant
reservoir Inverter coolant reservoir

4598-2. Steps to take in an emergency
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When trouble arises
The fuel cell stack coolant level
is satisfactory if it is between
the “FULL” and “LOW” lines on
the reservoir.
Fuel cell stack coolant reser-
voir
“FULL” line
“LOW” line
If the amount of fuel cell stack coolant is low:
Immediately contact your Toyota dealer.
If the amount of fuel cell st ack coolant is not low:
Have the vehicle inspected at the neare st Toyota dealer.
Even if the fuel cell stack cool-
ant is low, do not refill it.4

4608-2. Steps to take in an emergency
MIRAI_OM_USA_OM62073U■
If “FC System Overheat Output P
ower is Limited” is displayed
on the multi-information display
Stop the vehicle in a safe place and turn off the air conditioning
system, and then stop th e fuel cell system.
If you see steam or coolant leaks:
Carefully lift the hood after the steam subsides.
If you do not see steam or coolant leaks:
Carefully lift the hood.
After the fuel cell system has
cooled down, inspect the
hoses and radiator core
(radiator) for any leaks.
Inverter coolant radiator
Electric cooling fans
If a large amount of coolant
leaks, immediately contact
your Toyota dealer.
The inverter coolant level is
satisfactory if it is between
the “FULL” and “LOW” lines
on the reservoir.Inverter coolant reservoir
“FULL”
“LOW”
Add inverter cool ant if neces-
sary.
Water can be used in an emer-
gency if inverter coolant is
unavailable.
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4618-2. Steps to take in an emergency
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When trouble arises
Start the fuel cell system and turn the air conditioning system on
to check that the radiator coo ling fans operate and to check fo r
coolant leaks from t he radiator or hoses.
The fans operate when the air conditioning system is turned on immedi-
ately after a cold start. Confirm that the fans are operating b y checking
the fan sound and air flow. If it is difficult to check these, turn the air con-
ditioning system on and off repeatedly.
(The fans may not operate in freezing temperatures.)
If the fans are not operating:
Stop the fuel cell system immed iately and contact your Toyota
dealer.
If the fans are operating:
Have the vehicle inspected at the neare st Toyota dealer.
WARNING
■When inspecting under th e 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 motor compartment may be very hot.
● After the fuel cell system has been turned off, check that the “READY”
indicator is off.
When the fuel cell system is operating, the cooling fans may suddenly
operate even if the fuel cell system stops. Do not touch or app roach rotat-
ing parts such as the fans, which may lead to fingers or clothing (espe-
cially a tie, a scarf or a muffler) getting caught, resulting i n serious injury.
● Do not loosen the coolant reservoir caps or radiator cap, while the fuel cell
system and radiator are hot.
High temperature steam or coolant could spray out.
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