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678 4-3. Do-it-yourself maintenance
SIENNA_OM_OM45483U_(U)
Engine coolantThe coolant level is satisfactory if it is between the “FULL” and “LOW”
lines on the reservoir when the engine is cold.
Reservoir cap
“FULL”
“LOW”
If the level is on or below the
“LOW” line, add coolant up to the
“FULL” line.
■Coolant selection
Only use “Toyota Super Long Life Coolant” or 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 engine coolant, contact your Toyota dealer.
■ If the coolant level drops within a short time of replenishing
Visually check the radiator, hoses, engine coolant 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.
Page 679 of 872
679
4-3. Do-it-yourself maintenance
4
Maintenance and care
SIENNA_OM_OM45483U_(U)
CAUTION
■
When the engine is hot
Do not remove the engine coolant reservoir cap.
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 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.
Page 680 of 872

680 4-3. Do-it-yourself maintenance
SIENNA_OM_OM45483U_(U)
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.
CAUTION
■When the engine 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 fan is operating
Do not touch the engine compartment.
Vehicles without a smart key system: With the engine switch in the “ON”
position, the electric cooling fans may automatically start to run if the air con-
ditioning is on and/or the coolant temperature is high. Be sure the engine
switch is in the “LOCK” position when working near the electric cooling fan or
radiator grille.
Vehicles with a smart key system: With the “ENGINE START STOP” switch
in IGNITION ON mode, the electric cooling fans may automatically start to
run if the air conditioning is on and/or the coolant temperature is high. Be
sure the “ENGINE START STOP” switch is OFF when working near the elec-
tric cooling fans or radiator grille.
Page 741 of 872
5
When trouble arises
741
5-1. Essential information
SIENNA_OM_OM45483U_(U)
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
● Engine coolant temperature g auge needle continually points
higher than normal
■ 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 engine
■ Operational symptoms
●Engine missing, stumbling or running rough
● 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
Page 790 of 872
790
5-2. Steps to take in an emergency
SIENNA_OM_OM45483U_(U)
If your vehicle overheats
Correction proceduresStop the vehicle in a safe place and turn off the air condition-
ing system, and then stop the engine.
If you see steam: Carefully lift the hood after the steam subsides.
If you do not see steam: Carefully lift the hood.
After the engine has cooled
down sufficiently, inspect the
hoses and radiator core (radia-
tor) for any leaks.
Radiator
Cooling fans
If a large amount of coolant leaks,
immediately contact your Toyota
dealer.
The following may indicate that your vehicle is overheating:
●The needle of the engine co olant temperature gauge (P. 246)
enters the red zone or a loss of engine power is experienced.
(For example, the vehicl e speed does not increase.)
● Steam is coming from under the hood.
STEP1
STEP2
STEP5STEP3
Page 791 of 872
5
When trouble arises
791
5-2. Steps to take in an emergency
SIENNA_OM_OM45483U_(U)
The coolant level is satisfactory if
it is between the “FULL” and
“LOW” lines on the reservoir.
Reservoir
“FULL”
“LOW”
Radiator cap
Add coolant if necessary.
Water can be used in an emer-
gency if coolant is unavailable.
Start the engine 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 air conditioning system is turned on
immediately after a cold start. Conf irm that the fans are operating by
checking the fan sound and air flow. If it is difficult to check these,
turn the air conditioning system on and off repeatedly. (The fans may
not operate in freezing temperatures.)
If the fans are not operating:
Stop the engine immediately and contact your Toyota
dealer.
If the fans are operating: Have the vehicle inspected at the nearest Toyota dealer.
STEP4
STEP5
STEP6
STEP7
Page 792 of 872

792 5-2. Steps to take in an emergency
SIENNA_OM_OM45483U_(U)
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.
● Keep hands and clothing (especially a tie, a scarf or a muffler) away from
the fan and belts. Failure to do so may cause the hands or clothing to be
caught, resulting in serious injury.
● Do not loosen the radiator cap or the coolant reservoir cap while the
engine and radiator are hot. Serious injury, such as burns, may result from
hot coolant and steam released under pressure.
NOTICE
■When adding engine coolant
Wait until the engine has cooled down before adding engine coolant.
When adding coolant, do so slowly. Adding cool coolant to a hot engine too
quickly can cause damage to the engine.
■ 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.
Page 803 of 872
803
6-1. Specifications
6
Vehicle specifications
SIENNA_OM_OM45483U_(U)
Cooling system
Ignition system
Capacity
Without towing package
11.0 qt. (10.4 L, 9.2 Imp.qt.)
With towing package 11.7 qt. (11.1 L, 9.8 Imp.qt.)
Coolant type Use either of the following. • “Toyota Super Long Life Coolant”
• A similar high-quality ethylene glycol-based non-sili-cate, non-amine, non-nitrite, and non-borate coolant
with long-life hybrid organic acid technology
Do not use plain water alone.
Spark plug
Make
Gap DENSO FK20HR11
0.043 in. (1.1 mm)
NOTICE
■
Iridium-tipped spark plugs
Use only iridium-tipped spark plugs. Do not adjust spark plug gap.