2012 GMC YUKON engine overheat

Black plate (21,1)GMC Yukon/Yukon XL Owner Manual - 2012
Vehicle Care 10-21
4. With the coolant surge tankpressure cap off, start the
engine and let it run until the
upper radiator hose can be felt
getting hot. Watch out for the
engine cooling fan.
By this time, the coolant level
inside the coolant surge tank
may be lower. If the level is
lower, add more of the proper
mixture to the coolant surge tank
until the level reaches the FULL
COLD mark. 5. Replace the pressure cap. Be
sure the pressure cap is
hand-tight and fully seated.
6. Verify coolant level after engine is shut off and the coolant is
cold. If necessary, repeat coolant
fill procedure Steps 1 through 6.
Notice: If the pressure cap is not
tightly installed, coolant loss and
possible engine damage may
occur. Be sure the cap is properly
and tightly secured.
Engine Overheating
The vehicle has several indicators
to warn of engine overheating.
There is a coolant temperature
gauge on your vehicle's instrument
panel. See Engine Coolant
Temperature Gauge on page 5‑16. In addition, ENGINE OVERHEATED
STOP ENGINE, ENGINE
OVERHEATED IDLE ENGINE, and
an ENGINE POWER IS REDUCED
message comes on in the Driver
Information Center (DIC) on the
instrument panel. See
Engine
Cooling System Messages on
page 5‑39 andEngine Power
Messages on page 5‑41.
If the decision is made not to lift the
hood when this warning appears,
but instead get service help right
away. See Roadside Assistance
Program on page 13‑5.
If the decision is made to lift the
hood, make sure the vehicle is
parked on a level surface.

Black plate (22,1)GMC Yukon/Yukon XL Owner Manual - 2012
10-22 Vehicle Care
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
vehicle warranty. See Overheated
Engine Protection Operating
Mode on page 10‑23 for
information on driving to a safe
place in an emergency.
Notice: If the engine catches fire
while driving with no coolant, the
vehicle can be badly damaged.
The costly repairs would not be
covered by the vehicle warranty.
See Overheated Engine
Protection Operating Mode on
page 10‑23 for information on
driving to a safe place in an
emergency.If Steam Is Coming from the
Engine Compartment
{WARNING
Steam from an overheated engine
can burn you badly, even if you
just open the hood. Stay away
from the engine if you see or hear
steam coming from it. Turn it off
and get everyone away from the
vehicle until it cools down. Wait
until there is no sign of steam or
coolant before you open
the hood.
If you keep driving when the
vehicles engine is overheated,
the liquids in it can catch fire. You
or others could be badly burned.
Stop the engine if it overheats,
and get out of the vehicle until the
engine is cool.
(Continued)
WARNING (Continued)
SeeOverheated Engine
Protection Operating Mode on
page 10‑23 for information on
driving to a safe place in an
emergency.
If No Steam Is Coming from
the Engine Compartment
The ENGINE OVERHEATED
STOP ENGINE or the ENGINE
OVERHEATED IDLE ENGINE
message, along with a low coolant
condition, can indicate a serious
problem.
If an engine overheat warning is
displayed but no steam can be seen
or heard, the problem may not be
too serious. Sometimes the engine
can get a little too hot when the
vehicle:
.Climbs a long hill on a hot day.
.Stops after high-speed driving.

Black plate (23,1)GMC Yukon/Yukon XL Owner Manual - 2012
Vehicle Care 10-23
.Idles for long periods in traffic.
.Tows a trailer. SeeTrailer
Towing on page 9‑72.
If the overheat warning is displayed
with no sign of steam:
1. Turn the air conditioning off.
2. Turn the heater on to the highest temperature and to the highest
fan speed. Open the windows as
necessary.
3. In heavy traffic, let the engine idle in N (Neutral) while stopped.
If it is safe to do so, pull off the
road, shift to P (Park) or
N (Neutral) and let the
engine idle.
If the temperature overheat gauge
is no longer in the overheat zone
or an overheat warning no longer
displays, the vehicle can be driven.
Continue to drive the vehicle slowly
for about 10 minutes. Keep a safe
vehicle distance from the vehicle in
front. If the warning does not come
back on, continue to drive normally. If the warning continues, pull
over, stop, and park the vehicle
right away.
If there is no sign of steam, idle
the engine for three minutes
while parked. If the warning is still
displayed, turn off the engine until it
cools down. Also, see
“Overheated
Engine Protection Operating Mode”
later in this section.
Overheated Engine
Protection
Operating Mode
If an overheated engine condition
exists and the ENGINE POWER IS
REDUCED message is displayed,
an overheat protection mode which
alternates firing groups of cylinders
helps prevent engine damage. In
this mode, a loss in power and
engine performance will be noticed.
This operating mode allows the
vehicle to be driven to a safe place
in an emergency. Driving extended distances 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. See
Engine Oil on page 10‑8.
Engine Fan
If the vehicle has a clutched engine
cooling fan, when the clutch is
engaged, the fan spins faster to
provide more air to cool the engine.
In most everyday driving conditions,
the fan is spinning slower and the
clutch is not fully engaged.
This improves fuel economy and
reduces fan noise. Under heavy
vehicle loading, trailer towing, and/
or high outside temperatures, the
fan speed increases as the clutch

Black plate (4,1)GMC Yukon/Yukon XL Owner Manual - 2012
i-4 INDEX
DoorAjar Messages . . . . . . . . . . . . . . . 5-39
Delayed Locking . . . . . . . . . . . . . . . 2-8
Locks . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Power Locks . . . . . . . . . . . . . . . . . . . 2-8
Drive Belt Routing, Engine . . . . . 12-4
Driver Information Center (DIC) . . . . . . . . . . . . . . . . . 5-29
Driving Characteristics andTowing Tips . . . . . . . . . . . . . . . . . 9-68
Defensive . . . . . . . . . . . . . . . . . . . . . . 9-3
Drunk . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3
For Better Fuel Economy . . . . . 1-27
Highway Hypnosis . . . . . . . . . . . . 9-12
Hill and Mountain Roads . . . . . . 9-13
If the Vehicle is Stuck . . . . . . . . . 9-15
Loss of Control . . . . . . . . . . . . . . . . 9-5
Off-Road . . . . . . . . . . . . . . . . . . . . . . 9-6
Off-Road Recovery . . . . . . . . . . . . 9-5
Vehicle Load Limits . . . . . . . . . . . 9-16
Wet Roads . . . . . . . . . . . . . . . . . . . 9-11
Winter . . . . . . . . . . . . . . . . . . . . . . . . 9-13
Dual Automatic Climate Control System . . . . . . . . . . . . . . . . 8-4 DVD
Rear Seat Entertainment
System . . . . . . . . . . . . . . . . . . . . . . 7-34
DVD/CD Player . . . . . . . . . . . . . . . . 7-19
E
E85 Fuel . . . . . . . . . . . . . . . . . . . . . . . 9-64
Electrical Equipment, Add-On . . . . . . . . . . . . . . . . . . . . . . 9-86
Electrical System Engine CompartmentFuse Block . . . . . . . . . . . . . . . . 10-41
Fuses and Circuit
Breakers . . . . . . . . . . . . . . . . . . 10-40
Instrument Panel Fuse Block . . . . . . . . . . . . . . . . . . . . . . 10-45
Overload . . . . . . . . . . . . . . . . . . . 10-39
Emergency, OnStar
®. . . . . . . . . . 14-2
Engine Air Cleaner/Filter . . . . . . . . . . . 10-15
Check and Service EngineSoon Light . . . . . . . . . . . . . . . . . . 5-21
Compartment Overview . . . . . . . 10-6
Coolant . . . . . . . . . . . . . . . . . . . . . 10-17
Coolant Temperature
Gauge . . . . . . . . . . . . . . . . . . . . . . 5-16 Engine (cont'd)
Cooling System . . . . . . . . . . . . . 10-16
Cooling System Messages . . . 5-39
Drive Belt Routing . . . . . . . . . . . . 12-4
Exhaust . . . . . . . . . . . . . . . . . . . . . . 9-30
Fan . . . . . . . . . . . . . . . . . . . . . . . . . 10-23
Heater . . . . . . . . . . . . . . . . . . . . . . . . 9-26
Oil Pressure Gauge . . . . . . . . . . 5-15
Overheated Protection
Operating Mode . . . . . . . . . . . 10-23
Overheating . . . . . . . . . . . . . . . . 10-21
Power Messages . . . . . . . . . . . . . 5-41
Pressure Light . . . . . . . . . . . . . . . . 5-27
Running While Parked . . . . . . . . 9-30
Starting . . . . . . . . . . . . . . . . . . . . . . . 9-24
Engine Oil Life System . . . . . . . . . . . . . . . . . 10-10
Messages . . . . . . . . . . . . . . . . . . . . 5-40
Entry Lighting . . . . . . . . . . . . . . . . . . . 6-9
Equipment, Towing . . . . . . . . . . . . 9-76
Event Data Recorders . . . . . . . . 13-14
Exit Lighting . . . . . . . . . . . . . . . . . . . . 6-9
Extender, Safety Belt . . . . . . . . . . 3-28
Exterior Lamp Controls . . . . . . . . . 6-1
Exterior Lamps Off Reminder . . . 6-2

Black plate (9,1)GMC Yukon/Yukon XL Owner Manual - 2012
INDEX i-9
OnStar®
Additional Information . . . . . . . . 14-5
Connections . . . . . . . . . . . . . . . . . . 14-4
Diagnostics . . . . . . . . . . . . . . . . . . . 14-5
Emergency . . . . . . . . . . . . . . . . . . . 14-2
Navigation . . . . . . . . . . . . . . . . . . . . 14-2
Overview . . . . . . . . . . . . . . . . . . . . . 14-1
Security . . . . . . . . . . . . . . . . . . . . . . 14-2
OnStar
®System . . . . . . . . . . . . . . . 1-27
Operation, Infotainment System . . . . . . . . . . . . . . . . . . . . . . . . 7-3
Ordering Service Publications . . . . . . . . 13-12
Outlets Power . . . . . . . . . . . . . . . . . . . . . . . . . 5-9
Overheated Engine
Protection
Operating Mode . . . . . . . . . . . . . 10-23
Overheating, Engine . . . . . . . . . . 10-21
Overview, OnStar
®. . . . . . . . . . . . 14-1
P
Park Shifting into . . . . . . . . . . . . . . . . . . . 9-27
Shifting out of . . . . . . . . . . . . . . . . . 9-28
Park Tilt Mirrors . . . . . . . . . . . . . . . . 2-19
Parking Assist, Ultrasonic . . . . . . . . . . . . . 9-53
Brake . . . . . . . . . . . . . . . . . . . . . . . . . 9-45
Brake and P (Park)
Mechanism Check . . . . . . . . 10-33
Over Things That Burn . . . . . . . 9-29
Passenger Airbag Status Indicator . . . . . . . . . . . . . . . . . . . . . 5-19
Passenger Sensing System . . . 3-38
Perchlorate Materials Requirements, California . . . . . 10-3
Personalization Vehicle . . . . . . . . . . . . . . . . . . . . . . . 5-47
Phone Bluetooth . . . . . . . . . . . . . . . . . . . . . 7-47 Power
Door Locks . . . . . . . . . . . . . . . . . . . . 2-8
Mirrors . . . . . . . . . . . . . . . . . . . . . . . . 2-17
Outlets . . . . . . . . . . . . . . . . . . . . . . . . 5-9
Protection, Battery . . . . . . . . . . . . 6-10
Retained Accessory (RAP) . . . 9-27
Seat Adjustment . . . . . . . . . . . . . . . 3-4
Steering Fluid . . . . . . . . . . . . . . . 10-24
Windows . . . . . . . . . . . . . . . . . . . . . 2-21
Power Assist Steps . . . . . . . . . . . . 2-13
Pregnancy, Using Safety Belts . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
Privacy Radio FrequencyIdentification (RFID) . . . . . . . 13-16
Program
Courtesy Transportation . . . . . . 13-8
Proposition 65 Warning, California . . . . . . . . . . . . . . . . . . . . . 10-3