2009 CADILLAC DTS engine overheat

Turn Signals When Towing a Trailer
The arrows on the instrument panel ash whenever
signaling a turn or lane change. Properly hooked up,
the trailer lamps also ash, telling other drivers the
vehicle is turning, changing lanes or stopping.
When towing a trailer, the arrows on the instrument panel
ash for turns even if the bulbs on the trailer are burned
out. For this reason you may think other drivers are
seeing the signal when they are not. It is important to
check occasionally to be sure the trailer bulbs are still
working.
Driving on Grades
Notice:Do not tow on steep continuous grades
exceeding 6 miles (9.6 km). Extended, higher than
normal engine and transmission temperatures
may result and damage the vehicle. Frequent stops
are very important to allow the engine and
transmission to cool.
Reduce speed and shift to a lower gearbeforestarting
down a long or steep downgrade. If the transmission is
not shifted down, the brakes might have to be used so
much that they would get hot and no longer work well.
On a long uphill grade, shift down and reduce the
vehicle’s speed to around 45 mph (70 km/h) to reduce
the possibility of the engine and the transmission
overheating. If the engine does overheat, seeEngine
Overheating on page 5-28.
Parking on Hills
{CAUTION:
Parking the vehicle on a hill with the trailer
attached can be dangerous. If something goes
wrong, the rig could start to move. People can be
injured, and both the vehicle and the trailer can be
damaged. When possible, always park the rig on
a at surface.
If parking the rig on a hill:
1. Press the brake pedal, but do not shift into P (Park)
yet. Turn the wheels into the curb if facing downhill
or into traffic if facing uphill.
2. Have someone place chocks under the trailer
wheels.
3. When the wheel chocks are in place, release the
brake pedal until the chocks absorb the load.
4. Reapply the brake pedal. Then apply the parking
brake and shift the transmission into P (Park).
5. Release the brake pedal.
4-33

Leaving After Parking on a Hill
1. Apply and hold the brake pedal while you:
start the engine,
shift into a gear, and
release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the
chocks.
Maintenance When Trailer Towing
The vehicle needs service more often when pulling a
trailer. SeeScheduled Maintenance on page 6-4
for more information. Things that are especially
important in trailer operation are automatic transmission
uid, engine oil, belts, cooling system and brake
system. It is a good idea to inspect these before and
during the trip.
Check periodically to see that all hitch nuts and bolts
are tight.
Engine Cooling When Trailer Towing
The cooling system may temporarily overheat during
severe operating conditions. SeeEngine Overheating on
page 5-28.
Changing a Tire When Trailer Towing
If the vehicle gets a at tire while towing a trailer,
be sure to secure the trailer and disconnect it from the
vehicle before changing the tire.
4-34

Service............................................................5-3
Accessories and Modications..........................5-3
California Proposition 65 Warning.....................5-4
California Perchlorate Materials Requirements.....5-4
Doing Your Own Service Work.........................5-4
Adding Equipment to the Outside of
the Vehicle.................................................5-5
Fuel................................................................5-5
Gasoline Octane............................................5-5
Gasoline Specications....................................5-5
California Fuel...............................................5-5
Additives.......................................................5-6
Fuels in Foreign Countries...............................5-7
Filling the Tank..............................................5-7
Filling a Portable Fuel Container.......................5-9
Checking Things Under the Hood....................5-10
Hood Release..............................................5-11
Engine Compartment Overview.......................5-12
Engine Oil...................................................5-13
Engine Oil Life System..................................5-16
Engine Air Cleaner/Filter................................5-17
Automatic Transmission Fluid.........................5-19
Cooling System............................................5-22
Engine Coolant.............................................5-23
Coolant Surge Tank Pressure Cap..................5-27
Engine Overheating.......................................5-28Overheated Engine Protection
Operating Mode........................................5-30
Power Steering Fluid.....................................5-31
Windshield Washer Fluid................................5-32
Brakes........................................................5-33
Battery........................................................5-36
Jump Starting...............................................5-38
Headlamp Aiming...........................................5-43
Bulb Replacement..........................................5-46
High Intensity Discharge (HID) Lighting............5-46
Windshield Wiper Blade Replacement..............5-46
Tires..............................................................5-48
Tire Sidewall Labeling...................................5-49
Tire Terminology and Denitions.....................5-54
Ination - Tire Pressure.................................5-57
High-Speed Operation...................................5-59
Tire Pressure Monitor System.........................5-60
Tire Pressure Monitor Operation.....................5-61
Tire Inspection and Rotation...........................5-65
When It Is Time for New Tires.......................5-67
Buying New Tires.........................................5-68
Different Size Tires and Wheels......................5-69
Uniform Tire Quality Grading..........................5-70
Wheel Alignment and Tire Balance..................5-71
Wheel Replacement......................................5-71
Section 5 Service and Appearance Care
5-1

Automatic Transmission Fluid
When to Check and Change Automatic
Transmission Fluid
A good time to check the automatic transmission uid
level is when the engine oil is changed.
Change the uid and lter at the intervals listed in
Additional Required Services on page 6-5, and be sure
to use the transmission uid listed inRecommended
Fluids and Lubricants on page 6-11.
How to Check Automatic Transmission
Fluid
Because this operation can be a little difficult, you may
choose to have this done at the dealer/retailer service
department.
If you do it yourself, be sure to follow all the instructions
here or you could get a false reading on the dipstick.Notice:Too much or too little uid can damage
your transmission. Too much can mean that some
of the uid could come out and fall on hot engine
parts or exhaust system parts, starting a re.
Too little uid could cause the transmission to
overheat. Be sure to get an accurate reading if you
check your transmission uid.
Wait at least 30 minutes before checking the
transmission uid level if you have been driving:
When outside temperatures are above 90°F (32°C).
At high speed for quite a while.
In heavy traffic — especially in hot weather.
While pulling a trailer.
To get the right reading, the uid should be at normal
operating temperature, which is 180°F to 200°F
(82°C to 93°C).
Get the vehicle warmed up by driving about 15 miles
(24 km) when outside temperatures are above 50°F
(10°C). If it is colder than 50°F (10°C), you may have
to drive longer.
5-19

{CAUTION:
An electric engine cooling fan under the hood can
start up even when the engine is not running and
can cause injury. Keep hands, clothing, and tools
away from any underhood electric fan.
{CAUTION:
Heater and radiator hoses, and other engine parts,
can be very hot. Do not touch them. If you do, you
can be burned.
Do not run the engine if there is a leak. If you run
the engine, it could lose all coolant. That could
cause an engine re, and you could be burned.
Get any leak xed before you drive the vehicle.Notice:Using coolant other than DEX-COOL
®can
cause premature engine, heater core, or radiator
corrosion. In addition, the engine coolant could
require changing sooner, at 30,000 miles (50 000 km)
or 24 months, whichever occurs rst. Any repairs
would not be covered by the vehicle warranty.
Always use DEX-COOL
®(silicate-free) coolant in the
vehicle.
Engine Coolant
The cooling system in the vehicle is lled with
DEX-COOL®engine coolant. This coolant is designed
to remain in the vehicle for ve years or 150,000 miles
(240 000 km), whichever occurs rst.
The following explains the cooling system and how to
check and add coolant when it is low. If there is a
problem with engine overheating, seeEngine
Overheating on page 5-28.
5-23

What to Use
{CAUTION:
Adding only plain water to the cooling system can
be dangerous. Plain water, or some other liquid
such as alcohol, can boil before the proper coolant
mixture will. The vehicle’s coolant warning system
is set for the proper coolant mixture. With plain
water or the wrong mixture, the engine could get
too hot but you would not get the overheat
warning. The engine could catch re and you or
others could be burned. Use a 50/50 mixture of
clean, drinkable water and DEX-COOL
®coolant.Use a 50/50 mixture of clean, drinkable water and
DEX-COOL
®coolant. If using this mixture, nothing else
needs to be added. This mixture:
Gives freezing protection down to−34°F (−37°C),
outside temperature.
Gives boiling protection up to 265°F (129°C),
engine temperature.
Protects against rust and corrosion.
Will not damage aluminum parts.
Helps keep the proper engine temperature.
Notice:If an improper coolant mixture is used, the
engine could overheat and be badly damaged. The
repair cost would not be covered by the vehicle
warranty. Too much water in the mixture can freeze
and crack the engine, radiator, heater core, and other
parts.
Notice:If extra inhibitors and/or additives are used
in the vehicle’s cooling system, the vehicle could
be damaged. Use only the proper mixture of
the engine coolant listed in this manual for the
cooling system. SeeRecommended Fluids and
Lubricants on page 6-11for more information.
5-24

Checking Coolant
The vehicle must be on a level surface when checking
the coolant level.
Check to see if coolant is visible in the coolant recovery
tank. If the coolant inside the coolant recovery tank is
boiling, do not do anything else until it cools down. If
coolant is visible but the coolant level is not at or above
the FULL COLD mark, add a 50/50 mixture of clean,
drinkable water and DEX-COOL
®coolant at the coolant
recovery tank, but be sure the cooling system is cool
before this is done. SeeEngine Coolant on page 5-23for
more information.
How to Add Coolant to the Surge Tank
{CAUTION:
You can be burned if you spill coolant on hot
engine parts. Coolant contains ethylene glycol
and it will burn if the engine parts are hot enough.
Do not spill coolant on a hot engine.Notice:This vehicle has a specic coolant ll
procedure. Failure to follow this procedure could
cause the engine to overheat and be severely
damaged.
{CAUTION:
An electric engine cooling fan under the hood can
start up even when the engine is not running and
can cause injury. Keep hands, clothing, and tools
away from any underhood electric fan.
5-25

Engine Overheating
The vehicle has several indicators to warn of engine
overheating.
There is an engine temperature warning light and/or
gage on the instrument panel cluster. SeeEngine
Coolant Temperature Warning Light on page 3-59and
Engine Coolant Temperature Gage on page 3-60.
The vehicle may also display a ENGINE OVERHEATED
IDLE ENGINE message or an ENGINE OVERHEATED
STOP ENGINE message displayed in the Driver
Information Center (DIC). SeeDIC Warnings and
Messages on page 3-73for more information. You will
also hear a chime.
You may decide not to lift the hood when this warning
appears, but instead get service help right away.
SeeRoadside Service on page 7-7.If you do decide to lift the hood, make sure the vehicle
is parked on a level surface.
Then check to see if the engine cooling fans are
running. If the engine is overheating, both fans should
be running. If they are not, do not continue to run
the engine and have the vehicle serviced.
Notice:Engine damage from running the engine
without coolant is not covered by the warranty.
Notice:If the engine catches re while driving with
no coolant, the vehicle can be badly damaged.
The costly repairs would not be covered by
the vehicle warranty. SeeOverheated Engine
Protection Operating Mode on page 5-30for
information on driving to a safe place in an
emergency.
5-28