1999 GMC SIERRA coolant level

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4-58 Driving On Grades
Reduce speed and shift to a lower gear before 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.
If you have an automatic transmission, you can tow in
AUTOMATIC OVERDRIVE (
). You may want to
shift the transmission to THIRD (3) or, if necessary, a
lower gear selection if the transmission shifts too often
(e.g., under heavy loads and/or hilly conditions).
If you have a manual transmission and you are towing a
trailer, it's better not to use FIFTH (5) gear. Just drive in
FOURTH (4) gear (or, as you need to, a lower gear).
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 for an automatic transmission, or into
gear for a manual transmission.
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 shift into PARK (P) for an
automatic transmission, or REVERSE (R) for a
manual transmission.

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5-12
The coolant level should be at or above the COLD mark.
If it isn't, you may have a leak in the radiator hoses,
heater hoses, radiator, water pump or somewhere else in
the cooling system.
CAUTION:
Heater and radiator hoses, and other engine
parts, can be very hot. Don't touch them.
If you do, you can be burned.
Don't run the engine if there is a leak. If you run
the engine, it could lose all coolant. That could
cause an engine fire, and you could be burned.
Get any leak fixed before you drive the vehicle.
NOTICE:
Engine damage from running your engine
without coolant isn't covered by your warranty.
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.
If there seems to be no leak, start the engine again. See if
the engine cooling fan speed increases when idle speed is
doubled by pushing the accelerator pedal down. If it
doesn't, your vehicle needs service. Turn off the engine.

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5-13 How to Add Coolant to the Coolant
Recovery Tank (Gasoline Engines)
If you haven't found a problem yet, but the coolant level
isn't at or above the COLD mark, add a 50/50 mixture
of clean, drinkable water and DEX
-COOL
engine
coolant at the coolant recovery tank. (See ªEngine
Coolantº in the Index for more information.)
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.

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5-18
6. Start the engine and let it run until you can feel the
upper radiator hose getting hot. Watch out for the
engine cooling fan(s).
7. By this time, the coolant level inside the radiator
filler neck may be lower. If the level is lower, add
more of the proper DEX
-COOL
coolant mixture
through the filler neck until the level reaches the
base of the filler neck.
8. Then replace the pressure cap. At any time during
this procedure if coolant begins to flow out of the
filler neck, reinstall the pressure cap. Be sure the
arrows on the pressure cap line up like this.

6-
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6-1
Section 6 Service and Appearance Care
Here you will find information about the care of your vehicle. This section begins with service and fuel information,
and then it shows how to check important fluid and lubricant levels. There is also technical information about your
vehicle, and a part devoted to its appearance care.
6
-2 Service
6
-3 Fuel (Gasoline Engine)
6
-5 Fuels in Foreign Countries (Gasoline Engines)
6
-5 Filling Your Tank (Gasoline Engine)
6
-8 Filling a Portable Fuel Container
6
-8 Checking Things Under the Hood
6
-12 Noise Control System
6
-13 Engine Oil (Gasoline Engine)
6
-17 Engine Air Cleaner/Filter (Gasoline Engines)
6
-20 Automatic Transmission Fluid
6
-23 Manual Transmission Fluid
6
-24 Hydraulic Clutch
6
-25 Rear Axle
6
-26 Four-Wheel Drive
6
-27 Radiator Pressure Cap (Gasoline Engine)
6
-28 Thermostat
6
-28 Engine Coolant6
-32 Power Steering Fluid
6
-33 Windshield Washer Fluid
6
-34 Brakes
6
-38 Battery
6
-39 Bulb Replacement
6
-49 Windshield Wiper Blade Replacement
6
-50 Tires
6
-61 Appearance Care
6
-61 Cleaning the Inside of Your Vehicle
6
-65 Cleaning the Outside of Your Vehicle
6
-68 GM Vehicle Care/Appearance Materials
6
-69 Vehicle Identification Number (VIN)
6
-69 Electrical System
6
-75 Replacement Bulbs
6
-76 Capacities and Specifications
6
-78 Air Conditioning Refrigerants
6
-78 Normal Maintenance Replacement Parts

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6-30
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
If your vehicle has a diesel engine, see ªChecking
Coolantº in the Diesel Engine Supplement.
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 up to the HOT mark, or a
little higher.

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7-41
Part B: Owner Checks and Services
Listed in this part are owner checks and services which
should be performed at the intervals specified to help
ensure the safety, dependability and emission control
performance of your vehicle.
Be sure any necessary repairs are completed at once.
Whenever any fluids or lubricants are added to your
vehicle, make sure they are the proper ones, as shown in
Part D.
At the First 100, 1,000 and 6,000 Miles
(160, 1 600 and 10 000 km)
For vehicles with dual wheels, check dual wheel nut
torque. For proper torque, see ªWheel Nut Torqueº in
the Index.
At Each Fuel Fill
It is important for you or a service station attendant to
perform these underhood checks at each fuel fill.
Engine Oil Level Check
Check the engine oil level and add the proper oil if
necessary. See ªEngine Oilº in the Index for
further details.Engine Coolant Level Check
Check the engine coolant level and add DEX
-COOL

coolant mixture if necessary. See ªEngine Coolantº in
the Index for further details.
Windshield Washer Fluid Level Check
Check the windshield washer fluid level in the
windshield washer tank and add the proper fluid if
necessary. See ªWindshield Washer Fluidº in the Index
for further details.
At Least Once a Month
Tire Inflation Check
Make sure tires are inflated to the correct pressures.
See ªTiresº in the Index for further details.
Cassette Deck Service
Clean cassette deck. Cleaning should be done every
50 hours of tape play. See ªAudio Systemsº in the
Index for further details.

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9-4
Easy Entry Seat 1-6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrical Equipment, Adding 2-13, 3-27, 6-69 . . . . . . . . . . .
Electrical System 6-69 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrochromic Day/Night Rearview Mirror 2-45 . . . . . . . . . .
Engine 6-10, 6-11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Air Cleaner/Filter 6-17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Coolant 6-28, 6-76, 7-48 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Coolant Heater 2-15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Coolant Level Check 7-41 . . . . . . . . . . . . . . . . . . . . . . . . . .
Coolant Temperature Gage 2-69 . . . . . . . . . . . . . . . . . . . . .
Cooling System Capacity 6-77 . . . . . . . . . . . . . . . . . . . . . . .
Exhaust 2-31, 4-40 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuse Blocks 6-70, 6-73 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Identification 6-69 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Oil Level Check 7-41 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Overheating 5-9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Running While Parked 2-31 . . . . . . . . . . . . . . . . . . . . . . . . .
Specifications 6-76 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Starting Your 2-13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Underhood Fuse/Relay Center 6-73 . . . . . . . . . . . . . . . . . . .
Engine Oil 6-13, 7-48 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Adding 6-14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Additives 6-16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Checking 6-14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pressure Gage 2-72 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Used 6-17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
When to Change 6-16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exhaust, Engine 2-30, 4-40 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fabric Cleaning 6-61 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fan Control, Climate Control System 3-2, 3-3 . . . . . . . . . . . .
Fender Marker Lamp Bulb Replacement 6-44 . . . . . . . . . . . . .
Filling a Portable Fuel Container 6-8 . . . . . . . . . . . . . . . . . . . .
Filling Your Tank 6-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Filter, Air 6-17, 6-78 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Finish Care 6-65 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Finish Damage 6-67 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Flashers, Hazard Warning 5-2 . . . . . . . . . . . . . . . . . . . . . . . . .
Flat Tire, Changing 5-20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fluid Capacities 6-77 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fluids and Lubricants 7-48 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Foreign Countries, Fuel 6-5 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Four-Wheel Drive 2-21, 6-26 . . . . . . . . . . . . . . . . . . . . . . . . .
French Language Manual ii. . . . . . . . . . . . . . . . . . . . . . . . . . .
Front Axle 6
-27, 7-49 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front Axle Locking Feature 2-22 . . . . . . . . . . . . . . . . . . . . . . .
Front Towing 5-8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front Turn Signal Lamp Bulb Replacement 6-41, 6-42 . . . . .
Fuel 6-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Filling a Portable Container 6-8 . . . . . . . . . . . . . . . . . . . . . .
Filling Your Tank 6-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gage 2-75 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
In Foreign Countries 6-5 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tank Capacity 6-77 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuses and Circuit Breakers 6-70 . . . . . . . . . . . . . . . . . . . . . . .
Fusible Links 6-70 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .