engine overheat GMC YUKON 1999 User Guide

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5-13
CAUTION:
Adding only plain water to your cooling system
can be dangerous. Plain water, or some other
liquid like alcohol, can boil before the proper
coolant mixture will. Your vehicle's coolant
warning system is set for the proper coolant
mixture. With plain water or the wrong mixture,
your engine could get too hot but you wouldn't
get the overheat warning. Your engine could
catch fire 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. Don't spill coolant on a hot engine.

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5-32
Follow these instructions to restore a spare or flat tire:
1. Lay the tire on the ground at the rear of the vehicle.
Position the tire so that the valve stem is pointed
down and to the rear of the vehicle.
2. Tilt the retainer downward and through the wheel
opening. Make sure that the retainer is fully seated
across the underside of the wheel.
3. Attach the ratchet, with the UP mark facing you,
near the hook at the end of the jack handle. Insert the
other end, on an angle, through the hole in the rear
bumper and into the hoist shaft.
4. Raise the tire fully against the underside of the
vehicle. Continue turning the ratchet clockwise until
there are two ªclicksº or ªratchets.º The spare tire
hoist cannot be over
-tightened.
5. Grasp and push against the tire to be sure it is stored
securely and does not move.
If You're 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 don't want to spin your
wheels too fast. The method known as ªrockingº can
help you get out when you're stuck, but you must
use caution.
CAUTION:
If you let your 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 fire or other damage. When you're
stuck, spin the wheels as little as possible. Don't
spin the wheels above 35 mph (55 km/h) as shown
on the speedometer.

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6-23
NOTICE:
Your radiator cap is a 15 psi (105 kPa) pressure-type
cap and 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
overflow tube on the radiator filler neck.
Thermostat
Engine coolant temperature is controlled by a thermostat
in the engine coolant 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.
Engine Coolant
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.

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6-24
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 265F (129C).

Protect against rust and corrosion.

Help keep the proper engine temperature.

Let the warning 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.
What to Use
Use a mixture of one-half clean, drinkable water and
one
-half DEX-COOL coolant which won't damage
aluminum parts. If you use this coolant mixture, you
don't need to add anything else.
CAUTION:
Adding only plain water to your cooling system
can be dangerous. Plain water, or some other
liquid like alcohol, can boil before the proper
coolant mixture will. Your vehicle's coolant
warning system is set for the proper coolant
mixture. With plain water or the wrong mixture,
your engine could get too hot but you wouldn't
get the overheat warning. Your engine could
catch fire and you or others could be burned. Use
a 50/50 mixture of clean, drinkable water and
DEX
-COOL coolant.

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6-25
NOTICE:
If you use an improper coolant mixture, your
engine could overheat and be badly damaged.
The repair cost wouldn't be covered by your
warranty. Too much water in the mixture can
freeze and crack the engine, radiator, heater core
and other parts.
If you have to add coolant more than four times a year,
have your dealer check your cooling system.
NOTICE:
If you use the proper coolant, you don't have to
add extra inhibitors or additives which claim to
improve the system. These can be harmful.
Checking Coolant
The coolant recovery tank is located on the passenger's
side at the rear corner of the engine compartment.
The vehicle must be on a level surface. When your
engine is cold, the coolant level should be at the COLD
mark, or a little higher. When your engine is warm, the
level should be at the HOT mark, or a little higher.

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9-4
Electronic Compass 2-51 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Engine 6-10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Air Cleaner/Filter 6-15, 6-64 . . . . . . . . . . . . . . . . . . . . . . . .
Coolant 6-23, 7-41 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Coolant Heater 2-24 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Coolant Level Check 7-35 . . . . . . . . . . . . . . . . . . . . . . . . . .
Coolant Temperature Gage 2-76 . . . . . . . . . . . . . . . . . . . . .
Cooling System 6-64 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exhaust 2-36, 4-41 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Identification 6-55 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Oil Level Check 7-35 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Overheating 5-9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Running While Parked 2-37 . . . . . . . . . . . . . . . . . . . . . . . . .
Specifications 6-63 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Starting Your 2-22 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Engine Oil 6-11, 6-65, 7-41 . . . . . . . . . . . . . . . . . . . . . . . . . .
Adding 6-11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Additives 6-13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Checking 6-11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pressure Gage 2-79 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Used 6-14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
When to Change 6-14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Equipment, Adding to the Outside of Your Vehicle 6-3 . . . . . .
Ethanol 6-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exhaust, Engine 2-36, 4-41 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exit Lighting and Delayed Illumination 2-49 . . . . . . . . . . . . .
Exterior Lamps 2-46 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fabric Cleaning 6-47 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Feature Customization 2-16 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Driver's Door Alarm Delay 2-19 . . . . . . . . . . . . . . . . . . . . .
Keyless Entry Verification 2-17 . . . . . . . . . . . . . . . . . . . . . .
Leaving Programming Mode 2-19 . . . . . . . . . . . . . . . . . . . .
Lockout Prevention 2-17 . . . . . . . . . . . . . . . . . . . . . . . . . . . Theft
-Deterrent Arming Method 2-18 . . . . . . . . . . . . . . . . .
Theft-Deterrent Arming Verification 2-19 . . . . . . . . . . . . . .
Filling a Portable Fuel Container 6-8 . . . . . . . . . . . . . . . . . . . .
Filling Your Tank 6-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Filter, Air Cleaner 6-15, 6-64 . . . . . . . . . . . . . . . . . . . . . . . . .
Filter, Engine Oil 6-14, 6-64 . . . . . . . . . . . . . . . . . . . . . . . . . .
Finish Care 6-51 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Finish Damage 6-53 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
First Gear, Automatic Transmission 2-27 . . . . . . . . . . . . . . . .
Flashers, Hazard Warning 5-2 . . . . . . . . . . . . . . . . . . . . . . . . .
Flat Tire, Changing 5-19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fluid Capacities 6-63 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fluid Leak Check 6-33 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fluids and Lubricants 7-41 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fog Lamps 2-48, 6-36, 6-61 . . . . . . . . . . . . . . . . . . . . . . . . . .
Folding the Rear Seat 1-6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Foreign Countries, Fuel 6-5 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Four-Wheel Drive 2-28, 6-21 . . . . . . . . . . . . . . . . . . . . . . . . .
French Language Manual ii. . . . . . . . . . . . . . . . . . . . . . . . . . .
Front Axle 6
-22, 7-42 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front Axle Locking Feature 2-28 . . . . . . . . . . . . . . . . . . . . . . .
Front Park/Turn Signal Bulb Replacement 6-36, 6-61 . . . . . .
Front Sidemarker Lamp Bulb Replacement 6-36, 6-61 . . . . . .
Front Towing 5-8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel 6-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Canada 6-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Filling a Portable Container 6-8 . . . . . . . . . . . . . . . . . . . . . .
Filling Your Tank 6-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gage 2-82 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
In Foreign Countries 6-5 . . . . . . . . . . . . . . . . . . . . . . . . . . .
System Capacity 6-64 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuses and Circuit Breakers 6-57 . . . . . . . . . . . . . . . . . . . . . . .

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9-7
Mirrors 2-51 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Convex Outside 2
-55 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrochromic Day/Night Rearview with
Compass/Temperature Display/Headlamp Delay 2
-51 . . . . .
Electrochromic Heated Outside Rearview 2-54, 3-7 . . . . . .
Inside Rearview 2-51 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Remote Control 2-54 . . . . . . . . . . . . . . . . . . . . . . . . .
MMT 6-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Model Reference vi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mountain Roads 4
-36 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Multifunction Lever 2-40 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Net, Convenience 2-58 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Neutral, Automatic Transmission 2-26 . . . . . . . . . . . . . . . . . .
New Vehicle Break-In 2-20 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Night Vision 4-29 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Normal Maintenance Replacement Parts 6-65 . . . . . . . . . . . . .
Odometer 2-71 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Odometer, Trip 2-71 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Off-Road Driving 4-14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Off-Road Recovery 4-11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Oil, Engine 6-11, 6-65, 7-41 . . . . . . . . . . . . . . . . . . . . . . . . . .
OnStar
System 2-67 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Overdrive, Automatic Transmission 2-27 . . . . . . . . . . . . . . . .
Overheating Engine 5-9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Owner Checks and Services 7-35 . . . . . . . . . . . . . . . . . . . . . . .
Owner Publications, Ordering 8-12, 8-13 . . . . . . . . . . . . . . . .
Paint Spotting, Chemical 6-53 . . . . . . . . . . . . . . . . . . . . . . . .
Park
Automatic Transmission 2
-25 . . . . . . . . . . . . . . . . . . . . . . .
Shifting Into 2-33 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Shifting Out of 2-35 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Parking
At Night 2
-13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Brake 2-32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Brake Mechanism Check 7-38 . . . . . . . . . . . . . . . . . . . . . . .
Lots 2-13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Over Things That Burn 2-36 . . . . . . . . . . . . . . . . . . . . . . . .
With a Trailer 4-52 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Passenger Position 1-23 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Passing 4-12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Passlock
2-20, 2-80 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Periodic Maintenance Inspections 7-39 . . . . . . . . . . . . . . . . . .
Power
Auxiliary Outlet 2
-62 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Door Locks 2-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lumbar Adjustment 1-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Option Fuses 6-56 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Remote Control Mirror 2-54 . . . . . . . . . . . . . . . . . . . . . . . .
Seat 1-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Steering 4-9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Steering Fluid 6-27, 7-41 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Windows 2-38 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Lumbar Adjustment 1-3 . . . . . . . . . . . . . . . . . . . . . . . .
Pregnancy, Use of Safety Belts 1-22 . . . . . . . . . . . . . . . . . . . .
Problems on the Road 5-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Protecting Exterior Bright Metal Parts 6-52 . . . . . . . . . . . . . . .
Publications, Service and Owner 8-12, 8-13 . . . . . . . . . . . . . .