engine overheat GMC ENVOY 2007 Owner's Manual

Your vehicle has a Computer-Controlled
Cranking System. This feature assists in
starting the engine and protects components.
If the ignition key is turned to the START
position, and then released when the engine
begins cranking, the engine continues cranking
for a few seconds or until the vehicle starts.
If the engine does not start and the key is held
in START for many seconds, cranking stops
after 15 seconds to prevent cranking motor
damage. To prevent gear damage, this system
also prevents cranking if the engine is
already running. Engine cranking can be
stopped by turning the ignition switch to the
ACCESSORY or LOCK position.
Notice:Cranking the engine for long periods
of time, by returning the key to the START
position immediately after cranking has ended,
can overheat and damage the cranking
motor, and drain the battery. Wait at least
15 seconds between each try, to allow
the cranking motor to cool down.2. If the engine does not start after 5-10 seconds,
especially in very cold weather (below 0°F
or−18°C), it could be ooded with too much
gasoline. Try pushing the accelerator
pedal all the way to the oor and holding it
there as you hold the key in START for up to
a maximum of 15 seconds. Wait at least
15 seconds between each try, to allow the
cranking motor to cool down. When the engine
starts, let go of the key and accelerator.
If the vehicle starts briey but then stops
again, do the same thing. This clears the extra
gasoline from the engine. Do not race the
engine immediately after starting it. Operate
the engine and transmission gently until the oil
warms up and lubricates all moving parts.
Notice:Your engine is designed to work with
the electronics in your vehicle. If you add
electrical parts or accessories, you could
change the way the engine operates. Before
adding electrical equipment, check with your
dealer. If you do not, your engine might not
perform properly. Any resulting damage would
not be covered by your vehicle’s warranty.
115

{CAUTION:
Plugging the cord into an ungrounded
outlet could cause an electrical shock.
Also, the wrong kind of extension cord
could overheat and cause a re. You
could be seriously injured. Plug the cord
into a properly grounded three-prong
110-volt AC outlet. If the cord will not
reach, use a heavy-duty three-prong
extension cord rated for at least 15 amps.
4. Before starting the engine, be sure to unplug
and store the cord as it was before to keep it
away from moving engine parts. If you do
not, it could be damaged.How long should you keep the coolant heater
plugged in? The answer depends on the outside
temperature, the kind of oil you have, and
some other things. Instead of trying to list
everything here, we ask that you contact your
dealer in the area where you will be parking your
vehicle. The dealer can give you the best
advice for that particular area.
Active Fuel Management™
Your vehicle’s V8 engine may have Active Fuel
Management™. This system allows the engine to
operate on either all or half of its cylinders,
depending on your driving conditions.
When less power is required, such as cruising at a
constant vehicle speed, the system will operate
in the half cylinder mode, allowing your vehicle to
achieve better fuel economy. When greater
power demands are required, such as accelerating
from a stop, passing, or merging onto a freeway,
the system will maintain full-cylinder operation.
117

Leaving Your Vehicle With the
Engine Running
{CAUTION:
It can be dangerous to leave your vehicle
with the engine running. Your vehicle
could move suddenly if the shift lever is
not fully in PARK (P) with the parking
brake rmly set.
If you have four-wheel drive, your vehicle
will be free to roll – even if your lever is in
PARK (P) – if your transfer case is in
NEUTRAL. So be sure the transfer case is
in a drive gear – not NEUTRAL. See
Four-Wheel Drive on page 122.
And, if you leave the vehicle with the
engine running, it could overheat and
even catch re. You or others could be
injured. Do not leave your vehicle with the
engine running unless you have to.If you have to leave your vehicle with the engine
running, be sure your vehicle is in PARK (P)
and your parking brake is rmly set before you
leave it. After you have moved the shift lever into
PARK (P), hold the regular brake pedal down.
Then, see if you can move the shift lever
away from PARK (P) without rst pressing the
button on the console shift lever. If you can,
it means that the shift lever was not fully locked
into PARK (P).
128

StabiliTrak®Indicator Light
This warning light
should come on briey
when the engine is
started.
During most driving conditions, this light will not
come on. If the StabiliTrak
®System is actively
controlling the stability and/or traction of the
vehicle, this light will ash. This is normal.
This light will come on if any portion of the system
has been manually turned off or a problem is
detected in the system.
If your vehicle has a Driver Information Center, a
message will appear also, seeDIC Warnings
and Messages on page 222andStabiliTrak
®
System on page 309for more information.
Engine Coolant Temperature Gage
This gage shows the engine coolant temperature.
If the gage pointer moves into the red area, it
means that the engine coolant has overheated.
If you have been operating your vehicle under
normal driving conditions, you should pull off the
road, stop your vehicle and turn off the engine
as soon as possible.
SeeEngine Overheating on page 408for more
information.
United StatesCanada
208

ENGINE COOLANT HOT/ENGINE
OVERHEATED
Notice:If you drive your vehicle while the
engine is overheating, severe engine damage
may occur. If an overheat warning appears on
the instrument panel cluster and/or DIC, stop
the vehicle as soon as possible. Do not increase
the engine speed above normal idling speed.
SeeEngine Overheating on page 408for more
information.
This message displays and a chime sounds if the
cooling system temperature gets hot. See
Engine Overheating on page 408for the proper
course of action. This message clears when
the coolant temperature drops to a safe operating
temperature.
FUEL LEVEL LOW
This message displays and a chime sounds if the
fuel level is low in the vehicle’s fuel tank. Refuel as
soon as possible. Press any of the DIC buttons, or
the trip stem, to acknowledge this message and
clear it from the DIC display. SeeLow Fuel Warning
Light on page 217,Filling the Tank on page 385,
andFuel on page 382for more information.
ICE POSSIBLE
This message may display if the outside
temperature reaches a level where ice could form
on the roadway. If the temperature rises to a safe
level, the message clears. This message clears
itself after 10 seconds, or you can press any of the
DIC buttons, or the trip stem, to acknowledge this
message and clear it from the DIC display.
KEY FOB # BATTERY LOW
This message displays if a Remote Keyless Entry
(RKE) transmitter battery is low. Replace the
battery in the transmitter. See “Battery
Replacement” underRemote Keyless Entry (RKE)
System Operation on page 98. Press any of the
DIC buttons, or the trip stem, to acknowledge this
message and clear it from the DIC display.
LEFT REAR DOOR AJAR
This message displays and a chime sounds if the
driver’s side rear door is not fully closed. Stop and
turn off the vehicle, check the door for obstructions,
and close the door again. Check to see if the
message still appears on the DIC. Press any of the
DIC buttons, or the trip stem, to acknowledge this
message and clear it from the DIC display.
224

Driving Downhill
When off-roading takes you downhill, you will want
to consider a number of things:
How steep is the downhill? Will I be able to
maintain vehicle control?
What is the surface like? Smooth? Rough?
Slippery? Hard-packed dirt? Gravel?
Are there hidden surface obstacles? Ruts?
Logs? Boulders?
What is at the bottom of the hill? Is there a
hidden creek bank or even a river bottom
with large rocks?If you decide you can go down a hill safely, then
try to keep your vehicle headed straight down, and
use a low gear. This way, engine drag can help
the brakes and they will not have to do all
the work. Descend slowly, keeping your vehicle
under control at all times.
{CAUTION:
Heavy braking when going down a hill can
cause your brakes to overheat and fade.
This could cause loss of control and a
serious accident. Apply the brakes lightly
when descending a hill and use a low
gear to keep vehicle speed under control.
328

Q:Are there some things I should not do
when driving down a hill?
A:Yes! These are important because if you
ignore them you could lose control and
have a serious accident.
When driving downhill, avoid turns that take
you across the incline of the hill. A hill that
is not too steep to drive down may be
too steep to drive across. You could roll over
if you do not drive straight down.
Never go downhill with the transmission in
NEUTRAL (N). This is called “free-wheeling.”
The brakes will have to do all the work
and could overheat and fade.
Q:Am I likely to stall when going downhill?
A:It is much more likely to happen going uphill.
But if it happens going downhill, here is what
to do.
1. Stop your vehicle by applying the regular
brakes. Apply the parking brake.
2. Shift to PARK (P) and, while still braking,
restart the engine.
3. Shift back to a low gear, release the parking
brake, and drive straight down.
4. If the engine will not start, get out and
get help.
329

If Your Vehicle is Stuck in Sand,
Mud, Ice, or Snow
In order to free your vehicle when it is stuck,
you will need to spin the wheels, but you do not
want to spin your wheels too fast. The method
known as rocking can help you get out when you
are stuck, but you must use caution.
{CAUTION:
If you let your vehicle’s tires spin at high
speed, they can explode, and you or others
could be injured. And, the transmission or
other parts of the vehicle can overheat.
That could cause an engine compartment
re or other damage. When you are stuck,
spin the wheels as little as possible. Do not
spin the wheels above 35 mph (55 km/h) as
shown on the speedometer.Notice:Spinning the wheels can destroy
parts of your vehicle as well as the tires. If you
spin the wheels too fast while shifting the
transmission back and forth, you can destroy
the transmission.
For information about using tire chains on your
vehicle, seeTire Chains on page 461.
Rocking Your Vehicle to Get It Out
First, turn the steering wheel left and right. That will
clear the area around the front wheels. If you have
a four-wheel-drive vehicle, shift into Four-Wheel
High. Then shift back and forth between
REVERSE (R) and a forward gear, spinning the
wheels as little as possible. Release the accelerator
pedal while you shift, and press lightly on the
accelerator pedal when the transmission is in gear.
By slowly spinning the wheels in the forward and
reverse directions, you will cause a rocking motion
that may free your vehicle. If that does not get your
vehicle out after a few tries, it may need to be towed
out. If your vehicle does need to be towed out, see
Towing Your Vehicle on page 354.
348

Turn Signals When Towing a Trailer
The arrows on your instrument panel will
ash whenever you signal a turn or lane change.
Properly hooked up, the trailer lamps will also
ash, telling other drivers you’re about to
turn, change lanes or stop.
When towing a trailer, the arrows on your
instrument panel will ash for turns even if the
bulbs on the trailer are burned out. Thus, you may
think drivers behind you are seeing your signal
when they are not. It’s important to check
occasionally to be sure the trailer bulbs are
still working.
Driving On Grades
Reduce speed and shift to a lower gearbefore
you start down a long or steep downgrade. If you
don’t shift down, you might have to use your
brakes so much that they would get hot and no
longer work well.
You can tow in DRIVE (D). You may want to shift
the transmission to THIRD (3) or a lower gear,
under heavy loads or hilly conditions.
When towing at high altitude on steep uphill
grades, consider the following: Engine coolant will
boil at a lower temperature than at normal
altitudes. If you turn your engine off immediately
after towing at high altitude on steep uphill grades,
your vehicle may show signs similar to engine
overheating. To avoid this, let the engine run while
parked (preferably on level ground) with the
automatic transmission in PARK (P) for a few
minutes before turning the engine off. If you do get
the overheat warning, seeEngine Overheating
on page 408.
372

Service........................................................ 380
Accessories and Modications................... 380
California Proposition 65 Warning.............. 381
Doing Your Own Service Work.................. 381
Adding Equipment to the Outside of
Your Vehicle.......................................... 382
Fuel............................................................. 382
Gasoline Octane........................................ 382
Gasoline Specications.............................. 383
California Fuel........................................... 383
Additives................................................... 383
Fuels in Foreign Countries........................ 384
Filling the Tank......................................... 385
Filling a Portable Fuel Container............... 387
Checking Things Under the Hood.............. 388
Hood Release........................................... 388
Engine Compartment Overview.................. 390
Engine Oil................................................. 394
Engine Oil Life System.............................. 398
Engine Air Cleaner/Filter............................ 400
Automatic Transmission Fluid.................... 401
Engine Coolant.......................................... 405Radiator Pressure Cap.............................. 408
Engine Overheating................................... 408
Cooling System......................................... 411
Engine Fan Noise..................................... 416
Power Steering Fluid ................................. 417
Windshield Washer Fluid........................... 418
Brakes...................................................... 419
Battery...................................................... 422
Jump Starting............................................ 423
Rear Axle.................................................... 428
Four-Wheel Drive........................................ 428
Front Axle................................................... 429
Bulb Replacement....................................... 430
Halogen Bulbs........................................... 430
Headlamps................................................ 431
Front Turn Signal, Sidemarker and
Parking Lamps....................................... 432
Taillamps, Turn Signal, and Stoplamps...... 432
Back-Up Lamps......................................... 434
License Plate Lamp................................... 435
Replacement Bulbs................................... 435
Section 5 Service and Appearance Care
377