1999 CHEVROLET S10 radiator cap

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5-11
Cooling System
When you decide it's safe to lift the hood, here's what
you'll see:
A. Coolant Recovery Tank
B. Radiator Pressure Cap
C. Engine FanIf the coolant inside the coolant recovery tank is boiling,
don't do anything else until it cools down.
The coolant level should be at least up to the ADD
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.

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5-15
CAUTION:
Steam and scalding liquids from a hot cooling
system can blow out and burn you badly. They
are under pressure, and if you turn the radiator
pressure cap
-- even a little -- they can come out
at high speed. Never turn the cap when the
cooling system, including the radiator pressure
cap, is hot. Wait for the cooling system and
radiator pressure cap to cool if you ever have to
turn the pressure cap.

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5-16 How to Add Coolant to the Radiator
1. You can remove the radiator pressure cap when the
cooling system, including the radiator pressure cap and
upper radiator hose, is no longer hot. Turn the pressure
cap slowly counterclockwise until it first stops. (Don't
press down while turning the pressure cap.)
If you hear a hiss, wait for that to stop. A hiss means
there is still some pressure left.
2. Then keep turning the pressure cap, but now push
down as you turn it. Remove the pressure cap.

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5-17
3. Fill the radiator with the proper DEX-COOL

coolant mixture, up to the base of the filler neck.
(See ªEngine Coolantº in the Index for more
information about the proper coolant mixture.)
4. Then fill the coolant recovery tank to the ADD mark.
5. Put the cap back on the coolant recovery tank, but
leave the radiator pressure cap off.

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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.
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
6
-5 Fuels in Foreign Countries
6
-5 Filling Your Tank
6
-7 Filling a Portable Fuel Container
6
-8 Checking Things Under the Hood
6
-11 Engine Oil
6
-16 Engine Air Cleaner/Filter
6
-17 Automatic Transmission Fluid
6
-20 Manual Transmission Fluid
6
-21 Hydraulic Clutch
6
-22 Rear Axle
6
-23 Four-Wheel Drive
6
-25 Radiator Pressure Cap
6
-26 Thermostat
6
-26 Engine Coolant
6
-29 Power Steering Fluid6
-30 Windshield Washer Fluid
6
-31 Brakes
6
-35 Battery
6
-35 Bulb Replacement
6
-41 Windshield Wiper Blade Replacement
6
-43 Tires
6
-51 Appearance Care
6
-52 Cleaning the Inside of Your Vehicle
6
-54 Care of Safety Belts
6
-55 Cleaning the Outside of Your Vehicle
6
-59 GM Vehicle Care/Appearance Materials
6
-60 Vehicle Identification Number (VIN)
6
-60 Service Parts Identification Label
6
-61 Electrical System
6
-67 Replacement Bulbs
6
-67 Capacities and Specifications
6
-69 Air Conditioning Refrigerants

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6-25
When the differential is cold, add enough lubricant to
raise the level to 1/2 inch (12 mm) below the filler
plug hole.
When the differential is at operating temperature
(warm), add enough lubricant to raise the level to the
bottom of the filler plug hole.
What to Use
Refer to the Maintenance Schedule to determine what
kind of lubricant to use. See ªRecommended Fluids and
Lubricantsº in the Index.Radiator Pressure Cap
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.

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6-28 Checking Coolant
The vehicle must be on a level surface. When your
engine is cold, the coolant level should be at ADD, or a
little higher. When your engine is warm, the level should
be up to FULL HOT, or a little higher.
Adding Coolant
If you need more coolant, add the proper DEX
-COOL

coolant mixture at the coolant recovery tank.
CAUTION:
Turning the radiator pressure cap when the
engine and radiator are hot can allow steam and
scalding liquids to blow out and burn you badly.
With the coolant recovery tank, you will almost
never have to add coolant at the radiator.
Never turn the radiator pressure cap
-- even a
little
-- when the engine and radiator are hot.
Add coolant mixture at the recovery 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.