Page 478 of 572

08 SIENNA_U (L/O 0801)
470
2008 SIENNA from Aug. ’08 Prod. (OM45455U)
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 engine switch 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 518 of 572
08 SIENNA_U (L/O 0801)
510
2008 SIENNA from Aug. ’08 Prod. (OM45455U)
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 520 of 572

08 SIENNA_U (L/O 0801)
512
2008 SIENNA from Aug. ’08 Prod. (OM45455U)
If you perform maintenance by yourself,
be sure to follow the correct procedure
given in this Section.
You should be aware that improper or in-
complete servicing may result in operating
problems.
Performing do−it−yourself maintenance
during the warranty period may affect your
warranty coverage. Read the separate
Toyota Warranty statement for details and
suggestions.
This Section gives instructions only for
those items that are relatively easy for an
owner to perform. As explained in Section
6, there are still a number of items that
must be done by a qualified technician
with special tools.
For information on tools and Sections for
do− it−yourself maintenance, see “Parts
and tools” on page 515 in this Section.
Utmost care should be taken when work-
ing on your vehicle to prevent accidental
injury. Here are a few precautions that
you should be especially careful to ob-
serve:CAUTION
When the engine is running, keep
hands, clothing, and tools away
from the moving fan and engine
drive belts. (Removing rings,
watches, and ties is advisable.)
When the fan is operating after the
engine is turned off, do not touch
the engine compartment. Doing so
may result in injury or burn.
Right after driving, the engine
compartment—the engine, radiator,
exhaust manifold and spark plug
boots, etc.—will be hot. So be care-
ful not to touch them. Oil, fluids
and spark plugs may also be hot.
If the engine is hot, do not remove
the radiator cap or loosen the drain
plugs to prevent burning yourself.
Do not leave anything that may
burn easily, such as paper or rags,
in the engine compartment.
Do not smoke, cause sparks or al-
low open flames around fuel or the
battery. Their fumes are flammable.
Do not get under your vehicle with
just the body jack supporting it. Al-
ways use automotive jack stands or
other solid supports.
Be sure that the engine switch is
off if you work near the electric
cooling fans or radiator grille. With
the engine switch on, the electric
cooling fans will automatically start
to run if the engine coolant temper-
ature is high and/or the air condi-
tioning is on.
Use eye protection whenever you
work on or under your vehicle
where you may be exposed to flying
or falling material, fluid spray, etc.
Used engine oil contains potentially
harmful contaminants which may
cause skin disorders such as in-
flammation or skin cancer, so care
should be taken to avoid prolonged
and repeated contact with it. To re-
move used engine oil from your
skin, wash thoroughly with soap
and water.
Do not leave used oil within the
reach of children.
Do it yourself service
precautions
Page 528 of 572

08 SIENNA_U (L/O 0801)
520
2008 SIENNA from Aug. ’08 Prod. (OM45455U)
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