1999 GMC C-SERIES gas type

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6-8
NOTICE:
If you need a new cap, be sure to get the right
type. Your dealer can get one for you. If you get
the wrong type, it may not fit or have proper
venting, and your fuel tank and emissions system
might be damaged.
If you have dual tanks, fill the driver's side first. The
fuel gage will give better readings this way. Your gage
will show the average level of both tanks combined.
Filling a Portable Fuel Container
CAUTION:
Never fill a portable fuel container while it is in
your vehicle. Static electricity discharge from the
container can ignite the gasoline vapor. You can
be badly burned and your vehicle damaged if this
occurs. To help avoid injury to you and others:

Dispense gasoline only into
approved containers.

Do not fill a container while it is inside a
vehicle, in a vehicle's trunk, pickup bed or
on any surface other than the ground.

Bring the fill nozzle in contact with the
inside of the fill opening before operating
the nozzle. Contact should be maintained
until the filling is complete.

Don't smoke while pumping gasoline.
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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.
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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.
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6-44
Other Service Items
Component Box
Your vehicle has a component box along the left frame rail.
What is in the box depends on what options are on your
vehicle. Normally, the fuel filter, air dryer, Luberfiner oil
filter, emission canister or other components are in there.
To get into the box, you first have to remove the top
cover. To do that, remove the two 8 mm bolts on top and
the single 8 mm bolt at the top front. Then, pull the
cover toward you and lift it off.You can then remove the front cover if you need to, by
removing the two 8 mm bolts and pulling it off.
When you're through, be sure to put the front cover on,
before you put on the top cover.
Fuel Filter (Gasoline Engines)
The steel fuel filter is located inside the component box
at the rear. See your Maintenance Schedule for
recommended service intervals.
If your vehicle is equipped with the optional Davco
spin
-on type filter, it is also located in the component box.
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7-20
(16) = Check spring-to-axle U-bolts and shackle bolts
for proper torque. See the service manual for torque
sequence and specifications. When parts are replaced,
the torque must be checked and adjusted more often
during the first 6,000 miles (10 000 km). Check torque
at 500 miles (800 km) and 2,000 miles (3 000 km) after
first use of parts.
(17) = Check complete exhaust system and cab areas
near the exhaust system for broken, damaged, missing or
out
-of-position parts. Also inspect for open seams,
holes, loose connections or other conditions which could
let exhaust fumes seep into the driver compartment.
Needed repairs should be made at once. To help
maintain system integrity, replace exhaust pipes
whenever a new muffler is put on.
(18) = Check all engine drive belts for cracks, fraying,
wear and proper tension. Adjust or replace as needed.
(19) = Check throttle linkage for damaged or missing
parts (including throttle return springs), interference or
binding. Fix any problems at once. Do not lubricate
accelerator and cruise control cables.
(20) = With the engine off and below normal operating
temperature, check to see that the thermostatically
controlled engine cooling fan can be rotated by hand on
viscous
-operated drives. Replace as needed.(21) = Check shields and underhood insulation for
damage or looseness. Adjust or replace as needed.
(22) = Lubricate caliper housing, caliper support spring
and caliper support key.
(23) = Wheel bearing service:

Grease type
-- Clean, inspect and lubricate with the
proper wheel bearing grease at designated intervals
or when hubs are removed. See ªRecommended
Fluids and Lubricantsº in the Index.

Oil
-filled type -- Some wheel bearings are lubricated
by rear axle lubricant. When you have oil
-filled
hubs, use lubricant identical to that used in your rear
axle. Lubricant change intervals are the same for
front and rear axles. However, you must maintain oil
level at the OIL LEVEL mark between change
intervals. See ªRecommended Fluids and
Lubricantsº in the Index.
(24) = Check the air intake system installation to see
that gaskets are seated properly and all hose
connections, fasteners and other components are tight.
For gasoline engines, also check to be sure the air
cleaner housing is properly seated, that the cover fits
tightly and that the wing nut is tight. Tighten
connections and fasteners or replace parts as required.
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