1999 GMC SONOMA engine overheat

Table of Contents (cont'd)
Braking/Anti-lock Brakes (If Equipped)
Traction Control System
Steering
Driving Tips for Various Road ConditionsOff-Road Driving
Recreational Vehicle Towing
Loading Your Vehicle
Towing a Trailer Heating and Air Conditioning
Setting the Radio Clock
Radio/Cassette Player/CD PlayerRadio Theft-Deterrent Feature
Steering Wheel Controls (If Equipped)
Hazard Warning Flashers
Jump Starting
Towing Your VehicleEngine Overheating
Changing a Flat Tire
If You're Stuck
Problems on the Road
Section
3
Section
4
Section
5
Your Driving and the Road Comfort Controls and Audio Systems
iii

2-18 To Use the Engine Coolant Heater
1. Turn off the engine.
2. Open the hood and unwrap the electrical cord.
The cord is located on the driver's side of the engine
compartment, behind the underhood fuse block.
3. Plug it into a normal, grounded 110
-volt AC outlet.
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 fire. You could be seriously injured. Plug the
cord into a properly grounded three
-prong
11 0
-volt AC outlet. If the cord won't 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 don't, 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'll be parking your
vehicle. The dealer can give you the best advice for that
particular area.
Automatic Transmission Operation
Your automatic transmission has a shift lever on the
steering column.
There are several different positions for your shift lever.
It features an electronic shift position indicator within
the instrument cluster. This display must be powered
anytime the shift lever is capable of being moved out of
PARK (P). This means that if your key is in OFF, but
not locked, there will be a small current drain on your
battery which could discharge your battery over a period
of time. If you need to leave your key in the ignition in
OFF for an extended period, it is recommended that you
disconnect the battery cable from the battery to prevent
discharging your battery.
PARK (P): This locks your rear wheels. It's the best
position to use when you start your engine because your
vehicle can't move easily.

2-28

Move the lever up as far as it will go.
3. Turn the ignition key to LOCK.
4. Remove the key and take it with you. If you can
leave your vehicle with the key, your vehicle is in
PARK (P).
Leaving Your Vehicle With the Engine
Running (Automatic Transmission Only)
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 firmly set. And, if you
leave the vehicle with the engine running, it could
overheat and even catch fire. You or others could
be injured. Don't 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 firmly set before you leave it. After
you've 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 first pulling it
toward you. If you can, it means that the shift lever
wasn't fully locked into PARK (P).

2-60 Anti-Lock Brake System Warning Light
With the anti-lock brake
system, this light will come
on when you start your
engine and may stay on
for several seconds.
That's normal.
If the light stays on, or comes on when you're driving,
your vehicle needs service. If the regular brake system
warning light isn't on, you still have brakes, but you
don't have anti
-lock brakes. If the regular brake system
warning light is also on, you don't have anti
-lock brakes
and there's a problem with your regular brakes. See
ªBrake System Warning Lightº earlier in this section.
The anti
-lock brake system warning light should come
on briefly when you turn the ignition key to RUN. If the
light doesn't come on then, have it fixed so it will be
ready to warn you if there is a problem.
Engine Coolant Temperature Gage
United States Canada
This gage shows the engine coolant temperature.
If the gage pointer moves into the red area, your engine
is too hot!
It means that your 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.
The ªProblems on the Roadº section of this manual
shows you what to do. See ªEngine Overheatingº in
the Index.

4-21 Driving Downhill
When off-roading takes you downhill, you'll want to
consider a number of things:

How steep is the downhill? Will I be able to maintain
vehicle control?

What's the surface like? Smooth? Rough? Slippery?
Hard
-packed dirt? Gravel?

Are there hidden surface obstacles? Ruts?
Logs? Boulders?

What's 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 your brakes and
they won't 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.
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's not too
steep to drive down may be too steep to drive across.
You could roll over if you don't drive straight down.

Never go downhill with the transmission in
NEUTRAL (N), or with the clutch pedal depressed
in a manual shift. This is called ªfree
-wheeling.º
Your brakes will have to do all the work and could
overheat and fade.

4-53
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) (or the
manual transmission out of gear and the parking brake
applied) for a few minutes before turning the engine off.
If you do get the overheat warning, see ªEngine
Overheatingº in the Index.
Parking on Hills
CAUTION:
You really should not park your vehicle, with a
trailer attached, on a hill. If something goes
wrong, your rig could start to move. People can
be injured, and both your vehicle and the trailer
can be damaged.
But if you ever have to park your rig on a hill, here's
how to do it:
1. Apply your regular brakes, but don't shift into
PARK (P) yet, or into gear for a manual
transmission. When parking uphill, turn your wheels
away from the curb. When parking downhill, turn
your wheels into the curb.
2. Have someone place chocks under the trailer wheels.
3. When the wheel chocks are in place, release the
regular brakes until the chocks absorb the load.
4. Reapply the regular brakes. Then apply your
parking brake, and then shift into PARK (P), or
REVERSE (R) for a manual transmission.
5. Release the regular brakes.

5-
5-1
Section 5 Problems on the Road
Here you'll find what to do about some problems that can occur on the road.
5
-2 Hazard Warning Flashers
5
-2 Other Warning Devices
5
-3 Jump Starting
5
-7 Towing Your Vehicle
5
-8 Engine Overheating
5
-9 Cooling System5
-18 Engine Fan Noise
5
-18 If a Tire Goes Flat
5
-19 Changing a Flat Tire
5
-30 Compact Spare Tire (If Equipped)
5
-31 If You're Stuck: In Sand, Mud, Ice or Snow

5-8
Engine Overheating
You will find a coolant temperature gage on your
vehicle's instrument panel. See ªGagesº in the Index.
If Steam Is Coming From Your Engine
CAUTION:
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. Just 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 your engine is
overheated, the liquids in it can catch fire. You or
others could be badly burned. Stop your engine if
it overheats, and get out of the vehicle until the
engine is cool.
NOTICE:
If your engine catches fire because you keep
driving with no coolant, your vehicle can be
badly damaged. The costly repairs would not be
covered by your warranty.