Page 444 of 534

07 SIENNA_U (L/O 0612)
436
2007 SIENNA from Oct. ’06 Prod. (OM45437U)
If your engine coolant temperature
gauge indicates overheating, if you ex-
perience a loss of power, or if you hear
a loud knocking or pinging noise, the
engine has probably overheated. You
should follow this procedure...1. Pull safely off the road, stop the ve- hicle and turn on your emergency
flashers. Put the transmission in “P”
and apply the parking brake. Turn off
the air conditioning if it is being used.
2. If coolant or steam is boiling out of the radiator or reservoir, stop the engine.
Wait until the steam subsides before
opening the hood. If there is no coolant
boiling over or steam, leave the engine
running and make sure the electric
cooling fan is operating. If it is not,
turn the ignition off.
CAUTION
To help avoid personal injury, keep
the hood closed until there is no
steam. Escaping steam or coolant is
a sign of very high pressure.
3. Look for obvious coolant leaks from theradiator, hoses, and under the vehicle.
However, note that water draining from
the air conditioning is normal if it has
been used.
CAUTION
When the engine is running, keep
hands and clothing away from the
moving fan and engine drive belts.
4. If the coolant is leaking, stop the en-gine immediately. Call a Toyota dealer
for assistance.
5. If there are no obvious leaks, check the coolant reservoir. If it is dry, add
coolant to the reservoir while the en-
gine is running. Fill it about half full.
CAUTION
Do not attempt to remove the radiator
cap when the engine and radiator are
hot. Serious injury could result from
scalding hot fluid and steam blown
out under pressure.
6. After the engine coolant temperaturehas cooled to normal, again check the
coolant level in the reservoir. If neces-
sary, bring it up to half full again. Seri-
ous coolant loss indicates a leak in the
system. You s hould have it checked as
soon as possible at your Toyota dealer.
If your vehicle overheats
Page 477 of 534

07 SIENNA_U (L/O 0612)
469
2007 SIENNA from Oct. ’06 Prod. (OM45437U)
If you are a skilled do−it−yourself mechan-
ic, the Toyota service manuals are recom-
mended. Please be aware that do −it−your-
self maintenance can affect your warranty
coverage. See “Owner ’s Warranty Informa-
tion Booklet” or “Owner ’s Manual Supple-
ment” for the details. Listed below are the general maintenance
items that should be performed as fre-
quently as specified. In addition to check-
ing the items listed, if you notice any
unusual noise, smell or vibration, you
should investigate the cause or take your
vehicle to your Toyota dealer or a quali-
fied service shop immediately. It is recom-
mended that any problem you notice be
brought to the attention of your dealer or
the qualified service shop for their advice.
CAUTION
Make these checks only with ade-
quate ventilation if you run the en-
gine.
IN THE ENGINE COMPARTMENT
Items listed below should be checked
from time to time, e.g. each time when
refueling.
Washer fluid
Make sure there is sufficient fluid in the
tank. See page 503 in Section 7
−3 for
additional information. Engine coolant level
Make sure the coolant level is between
the “FULL” and “LOW” lines on the see
−
through reservoir when the engine is cold.
See page 484 in Section 7 −2 for addition-
al information.
Radiator, condenser and hoses
Check that the front of the radiator and
condenser are clean and not blocked with
leaves, dirt, or insects. See page 485 in
Section 7 −2 for additional information.
Battery condition
Check the battery condition by the indica-
tor color. See page 500 in Section 7 −3 for
additional information.
Brake fluid level
Make sure the brake fluid level is correct.
See page 485 in Section 7 −2 for addition-
al information.
Engine oil level
Check the level on the dipstick with the
engine turned off and the vehicle parked
on a level spot. See page 482 in Section
7 −2 for additional information.
General maintenance
Page 482 of 534
07 SIENNA_U (L/O 0612)
474
2007 SIENNA from Oct. ’06 Prod. (OM45437U)
1. Power steering fluid reservoir
2. Windshield and rear window washerfluid tank
3. Engine oil filler cap
4. Engine oil level dipstick
5. Engine coolant reservoir
6. Brake fluid reservoir
7. Fuse block
8. Battery
9. Electric cooling fans
10. Condenser
11. Radiator
Engine compartment overview
Page 492 of 534

07 SIENNA_U (L/O 0612)
484
2007 SIENNA from Oct. ’06 Prod. (OM45437U)
To ensure excellent lubrication perfor-
mance for your engine, “Toyota Genuine
Motor Oil” is available, which has been
specifically tested and approved for all
Toyota engines.
Please contact your Toyota dealer for fur-
ther details about “Toyota Genuine Motor
Oil”.Look at the see through coolant reser-
voir when the engine is cold. The cool-
ant level is satisfactory if it is between
the “FULL” and “LOW” lines on the
reservoir. If the level is low, add the
coolant. (For the coolant type, see
“Coolant type selection” described be-
low.)
The coolant level in the reservoir will vary
with engine temperature. However, if the
level is on or below the “LOW” line, add
coolant. Bring the level up to the “FULL”
line.
If the coolant level drops within a short
time after replenishing, there may be a
leak in the system. Visually check the
radiator, hoses, engine coolant filler cap,
radiator cap and drain cock and water
pump.
If you can find no leak, have your Toyota
dealer test the cap pressure and check
for leaks in the cooling system.
CAUTION
To prevent burning yourself, do not
remove the radiator cap when the en-
gine is hot.
Coolant type selection
Use of improper coolants may damage
your engine cooling system.
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. (Coolant
with long −life hybrid organic acid
technology is a combination of low
phosphates and organic acids.)
For the U.S.A.—“Toyota Super Long Life
Coolant” is a mixture of 50% coolant and
50% deionized water. This coolant pro-
vides protection down to about −35 C
( − 31 F).
For Canada—“Toyota Super Long Life
Coolant” is a mixture of 55% coolant and
45% deionized water. This coolant pro-
vides protection down to about −42 C
( − 44 F).
NOTICE
Do not use plain water alone.
Checking the engine coolant
level
Page 493 of 534

07 SIENNA_U (L/O 0612)
485
2007 SIENNA from Oct. ’06 Prod. (OM45437U)
Toyota recommends “Toyota Super Long
Life Coolant”, which has been tested to
ensure that it will not cause corrosion nor
result in malfunction of your engine
coolant system with proper usage. “Toyota
Super Long Life Coolant” is formulated
with long−life hybrid organic acid
technology and has been specifically
designed to avoid engine cooling system
malfunction on Toyota vehicles.
Please contact your Toyota dealer for
further details. If any of the above parts are extremely
dirty or you are not sure of their condi-
tion, take your vehicle to a Toyota dealer.
CAUTION
To prevent burning yourself, be care-
ful not to touch the radiator or con-
denser when the engine is hot.
NOTICE
To prevent damage to the radiator
and condenser, do not perform the
work by yourself.
To check the fluid level, simply look at
the see through reservoir. The level
should be between the “MAX” and
“MIN” lines on the reservoir.
It is normal for the brake fluid level to go
down slightly as the brake pads wear. So
be sure to keep the reservoir filled.
If the reservoir needs frequent refi
lling, it
may indicate a serious mechanical prob-
lem.
Checking the radiator and
condenser Checking brake fluid