2008 CADILLAC DTS engine overheat

If you get the overheat warning with no sign of steam,
try this for a minute or so:
1. In heavy traffic, let the engine idle in NEUTRAL (N)
while stopped. If it safe to do so, pull off the road,
shift to PARK (P) or NEUTRAL (N) and let the
engine idle.
2. Set the climate controls to the highest heat setting
and fan speed and open the windows as necessary.
If you no longer have the overheat warning, you
can drive. Just to be safe, drive slower for about
10 minutes. If the warning does not come back on,
you can drive normally.
If the warning continues, pull over, stop, and park your
vehicle right away.
If there is still no sign of steam, idle the engine for
three minutes while you are parked. If you still have the
warning, turn off the engine and get everyone out of
the vehicle until it cools down. Also, see “Overheated
Engine Protection Operating Mode” later in this section.
You may decide not to lift the hood but to get service
help right away.Overheated Engine Protection
Operating Mode
If an overheated engine condition exists and the
message ENGINE OVERHEATED STOP ENGINE is
displayed, an overheat protection mode which alternates
ring groups of cylinders helps prevent engine damage.
In this mode, you will notice a loss in power and engine
performance. This operating mode allows your vehicle
to be driven to a safe place in an emergency. Driving
extended miles (km) and/or towing a trailer in the
overheat protection mode should be avoided.
Notice:After driving in the overheated engine
protection operating mode, to avoid engine damage,
allow the engine to cool before attempting any
repair. The engine oil will be severely degraded.
Repair the cause of coolant loss, change the oil
and reset the oil life system. SeeEngine Oil
on page 5-15.
5-29

{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.
If the coolant inside the coolant surge tank is boiling,
do not do anything else until it cools down. The vehicle
should be parked on a level surface.
{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.If there seems to be no leak, with the engine on, check
to see if the electric engine cooling fans are running.
If the engine is overheating, both fans should be
running. If they are not, your vehicle needs service.
Notice:Engine damage from running your engine
without coolant is not covered by your warranty. See
Overheated Engine Protection Operating Mode on
page 5-29for information on driving to a safe place
in an emergency.
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.
5-31

{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.
Notice:In cold weather, water can freeze and crack
the engine, radiator, heater core and other parts.
Use the recommended coolant and the proper
coolant mixture.
{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.
1. You can remove the
coolant surge tank
pressure cap when
the cooling system,
including the coolant
surge tank pressure
cap and upper radiator
hose, is no longer hot.
Turn the pressure cap slowly counterclockwise.
If you hear a hiss, wait for that to stop. A hiss
means there is still some pressure left.
5-33

Electronic Immobilizer Operation
PASS-Key®III+...........................................2-21
Engine
Air Cleaner/Filter.........................................5-20
Check and Service Engine Soon Light............3-65
Coolant......................................................5-24
Coolant Heater............................................2-26
Coolant Temperature Gage...........................3-64
Coolant Temperature Warning Light................3-63
Drive Belt Routing.......................................6-15
Engine Compartment Overview......................5-14
Exhaust.....................................................2-34
Oil .............................................................5-15
Oil Life System...........................................5-18
Overheated Protection Operating Mode...........5-29
Overheating................................................5-27
Starting......................................................2-24
Entry Lighting.................................................3-37
Event Data Recorders.....................................7-18
Extender, Safety Belt.......................................1-30
Exterior Lamps...............................................3-32
Exterior Lighting Battery Saver..........................3-37F
Filter
Engine Air Cleaner......................................5-20
Finish Damage...............................................5-97
Flashers, Hazard Warning.................................. 3-6
Flash-to-Pass.................................................3-13
Flat Tire........................................................5-78
Flat Tire, Changing.........................................5-79
Flat Tire, Storing.............................................5-87
Floor Mats.....................................................2-60
Fluid
Automatic Transmission................................5-21
Power Steering...........................................5-35
Windshield Washer......................................5-36
Fog Lamp
Fog ...........................................................3-36
Fog Lamp Light..............................................3-68
Footwell Lamps..............................................3-38
Forward Collision Alert (FAC) System................3-10
Front Storage Area.........................................2-59
5

Message
DIC Warnings and Messages........................3-75
Mirrors
Automatic Dimming Rearview........................2-36
Manual Rearview Mirror with Compass and
Temperature.............................................. 1-9
Outside Automatic Dimming Mirror.................2-39
Outside Convex Mirror.................................2-39
Outside Heated Mirrors................................2-39
Outside Power Foldaway Mirrors....................2-38
Park Tilt .....................................................2-39
MP3 ............................................................3-111
MyGMLink.com................................................ 7-5
N
Navigation System, Privacy..............................7-19
Navigation/Radio System,
see Navigation Manual...............................3-118
New Vehicle Break-In......................................2-22
O
Odometer......................................................3-55
Off-Road Recovery..........................................4-10
Oil
Engine.......................................................5-15
Pressure Light.............................................3-67
Oil, Engine Oil Life System..............................5-18
Older Children, Restraints................................1-31
Online Owner Center........................................ 7-5
OnStar, Privacy..............................................7-19
OnStar
®System, see OnStar®Manual...............2-49
Operation, Universal Home Remote System........2-52
Other Warning Devices...................................... 3-6
Outlet Adjustment............................................3-48
Outlets
Accessory Power.........................................3-40
Outside
Automatic Dimming Mirror.............................2-39
Convex Mirror.............................................2-39
Heated Mirrors............................................2-39
Power Foldaway Mirrors...............................2-38
Overheated Engine Protection Operating Mode....5-29
Owner Checks and Services.............................. 6-9
Owners, Canadian............................................... ii
9