overheating GMC C-SERIES 1999 Owners Manual

yellowblue
2-8 Manual Transmission
Set the parking brake, shift your gear selector to
NEUTRAL and hold the clutch pedal to the floor while
starting the engine.
Starter Motor Operation
1. The starter motor will disengage if you release
the key or the engine reaches a predetermined
engine speed.
2. To prevent overheating, the starter motor will
disengage after continuously operating for 15 seconds.
You must release the key from the start position to
re
-engage the starter.
3. The starter motor will not engage if the engine is
already running.
4. The starter motor will disengage if, after two
seconds, the starter pinion gear does not engage the
flywheel or there is no engine rpm signal from the
engine speed sensor.
Starting Your Engine
1. Without pushing the accelerator pedal, turn your
ignition key to START. When the engine starts, let
go of the key. The idle speed will go down as your
engine gets warm.
2. If the engine doesn't start in 10 seconds, push the
accelerator pedal all the way down and crank the
engine for five more seconds, unless it starts sooner.
3. If your engine still won't start (or starts but then
stops), it could be flooded with too much gasoline.
Wait 15 seconds to let the starter motor cool down.
Do Steps 1 through 3 again.
When the engine starts, let go of the key and the
accelerator pedal.
ProCarManuals.com

yellowblue
2-13
The manual fast idle feature is activated by pressing the
switch on the instrument panel. When the switch is
pressed again, or any of the previous conditions are not
met, manual fast idle will be deactivated.
Manual fast idle can be used to set any desired idle
speed. To set a new temporary engine idle speed:
1. Make sure all of the previously described conditions
are met.
2. Press the accelerator pedal to the desired engine speed.
3. Momentarily press the manual FAST IDLE switch.
The temporary idle speed will be set. This new rpm
level will be remembered by the system until either the
ignition is turned to OFF or a new idle speed is set.
Radiator Shutters -- Caterpillar

(If Equipped)
Radiator shutters aid engine warm-up by blocking the
airflow through the radiator and charge the air cooler to
conserve heat in cold conditions.
The radiator shutters on your vehicle (if equipped)
operate automatically. When the ignition switch is in
RUN or START and the engine temperature is below
195F (90C), the shutters will close, blocking the flow
of air through the radiator and charge the air cooler.When the engine temperature reaches 195F (90C), the
shutters will open to the normal operating position.
Engine Checks Before Operating
When you've started your engine, let it run for 20 to
30 seconds before you put a load on the engine.
But don't leave the vehicle while the engine is running.
During this warm
-up period, check your warning lights
and gages:

If oil pressure doesn't begin to rise within 15 seconds
of starting, stop the engine and find the cause.

If the engine coolant temperature gage needle goes
into the hot area on the gage, stop the engine and
find the cause of the overheating.

If you have air brakes, the dual
-needle air pressure
gage should read at least 105 psi (720 kPa) for both
service systems before you try to move the vehicle.
When air pressure is below 60 psi (420 kPa), the
LOW AIR light will come on and you will hear a
tone alarm. If the pressure doesn't build up or drops
during warm
-up, stop the engine and find the cause
before you try to move the vehicle. Recommended
air pressure before actually driving away is
120 psi (830 kPa).
ProCarManuals.com

yellowblue
2-61 Anti-Lock Brake System Warning Light
(Option)
With the anti-lock brake
system, this light will come
on when you start your
engine and it 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 PRIMARY BRAKE or
LOW AIR warning light isn't on, you still have brakes,
but you don't have the anti
-lock brake feature. If the
PRIMARY BRAKE and/or LOW AIR warning light is
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
Gasoline Engine Diesel Engine
This gage shows the engine coolant temperature. If
the gage pointer moves into the red area, your engine
coolant might have overheated and your engine may be
too hot. You should pull off the road, stop your vehicle
and turn off the engine as soon as possible.
See ªEngine Overheatingº in the Index. If you have a
Caterpillar

diesel engine, also see your Caterpillar

Operation & Maintenance Manual.
ProCarManuals.com

5-
yellowblue
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
-3 Other Warning Devices
5
-5 Jump Starting
5
-9 Towing Your Vehicle
5
-18 Engine Overheating
5
-20 Cooling System (Gasoline Engine)5
-27 Cooling System (Diesel Engine)
5
-33 Engine Fan Noise
5
-34 If a Tire Goes Flat
5
-34 Changing a Flat Tire
5
-37 If You're Stuck: In Sand, Mud, Ice or Snow
ProCarManuals.com

yellowblue
5-18
Engine Overheating
You will find a coolant temperature warning gage on
your vehicle's instrument panel, as well as a LOW
COOLANT warning light. Your vehicle also has a
CHECK GAGES warning light on the instrument panel.
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.
ProCarManuals.com

yellowblue
6-21
Radiator Pressure Cap
(Gasoline Engines)
The radiator pressure cap
must be tightly installed
with the arrows on the cap
lined up with the top of the
overflow tube. This will
prevent coolant loss and
possible engine damage
from overheating.
When you replace your radiator pressure cap, an
ACDelco

cap is recommended.
NOTICE:
Your radiator pressure cap is a 9 psi (62kPa)
pressure
-type cap for use with medium duty
cooling systems only. It must be tightly installed
to prevent coolant loss and possible engine
damage from overheating. Be sure the arrows on
the cap line up with the top of the overflow tube.
ProCarManuals.com

yellowblue
6-22
Surge Tank Pressure Cap
(Diesel Engines)
The surge tank pressure cap
must be tightly installed
with the arrows on the cap
lined up with the top tube of
the coolant surge tank.
When you replace your surge tank pressure cap, an
ACDelco

cap is recommended.
NOTICE:
Your surge tank pressure cap is a 9 psi (62kPa)
pressure
-type cap for use with medium duty
cooling systems only. It must be tightly installed
to prevent coolant loss and possible engine
damage from overheating. Be sure the arrows on
the cap line up with the top tube of the coolant
surge tank.
Thermostat
Engine coolant temperature is controlled by one or more
thermostats in the engine cooling system. The
thermostat stops the flow of coolant through the radiator
until the coolant reaches a preset temperature.
When you replace your thermostat, an ACDelco


thermostat is recommended for gasoline engines.
Caterpillar
parts are recommended for diesel engines.
ProCarManuals.com

yellowblue
6-23
Engine Coolant (Gasoline Engine)
The cooling system in your vehicle is filled with
DEX
-COOL
engine coolant. This coolant is designed
to remain in your vehicle for 5 years or 150,000 miles
(240 000 km), whichever occurs first, if you add only
DEX
-COOL
extended life coolant.
The following explains your cooling system and how to
add coolant when it is low. If you have a problem with
engine overheating, see ªEngine Overheatingº in
the Index.
A 50/50 mixture of clean, drinkable water and
DEX
-COOL
coolant will:

Give freezing protection down to
-34F (-37C).

Give boiling protection up to 252F (122C).

Protect against rust and corrosion.

Help keep the proper engine temperature.

Let the warning lights and gages work as
they should.
NOTICE:
When adding coolant, it is important that you
use only DEX
-COOL (silicate-free) coolant.
If coolant other than DEX-COOL is added to
the system, premature engine, heater core or
radiator corrosion may result. In addition, the
engine coolant will require change sooner
-- at
30,000 miles (50 000 km) or 24 months,
whichever occurs first. Damage caused by the
use of coolant other than DEX
-COOL is not
covered by your new vehicle warranty.
ProCarManuals.com

yellowblue
6-27
CAUTION:
Turning the radiator pressure cap (on a gasoline
engine) or the surge tank cap (on a diesel engine)
when the engine and radiator are hot can allow
steam and scalding liquids to blow out and burn
you badly. With the coolant recovery system, you
will almost never have to add coolant at the
radiator. Never turn the radiator pressure cap
or the surge tank pressure cap
-- even a
little
-- when the engine and radiator are hot.
Add coolant mixture at the recovery tank or the surge
tank, but be careful not to spill it.
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. Don't spill coolant on a hot engine.
Some conditions, such as trapped air in the cooling
system, can affect the coolant level in the radiator. If you
need to add coolant to the radiator, follow the steps
listed under ªHow to Add Coolant to the Radiator.º
See ªEngine Overheatingº in the Index.
Engine Coolant
(Caterpillar
Diesel Engine)
If your vehicle has a Caterpillar diesel engine, see the
Caterpillar
Operation & Maintenance Manual provided
with your vehicle to find out what to add, also when and
how to service your cooling system.
ProCarManuals.com

yellowblue
6-48 Muffler/Catalytic Converter Assemblies
(Diesel Engines)
Some vehicles equipped with a Caterpillar
diesel engine
utilize a catalytic converter
-muffler assembly. If your
vehicle is equipped with a catalytic converter
-muffler,
some special procedures may need to be followed when
servicing your vehicle. Consult your GM Truck dealer
who is an authorized Caterpillar

engine dealer
for service.
To determine your vehicle's muffler type, examine the
muffler outer housing. If your system is a catalytic
converter
-muffler type, the housing will be stamped
with the CAT logo.
Tires
Your new vehicle comes with high-quality tires made by
a leading tire manufacturer. If you ever have questions
about your tire warranty and where to obtain service, see
your GM Warranty booklet for details.
CAUTION:
Poorly maintained and improperly used tires
are dangerous.

Overloading your tires can cause
overheating as a result of too much friction.
You could have an air
-out and a serious
accident. See ªLoading Your Vehicleº in
the Index.

Underinflated tires pose the same danger as
overloaded tires. The resulting accident
could cause serious injury. Check all tires
frequently to maintain the recommended
pressure. Tire pressure should be checked
when your tires are cold.

Overinflated tires are more likely to be cut,
punctured or broken by a sudden
impact
-- such as when you hit a pothole.
Keep tires at the recommended pressure.

Worn, old tires can cause accidents. If your
tread is badly worn, or if your tires have
been damaged, replace them.
ProCarManuals.com