Page 449 of 594

4. With the coolant surge tank pressure cap off, start
the engine and let it run until you can feel the upper
radiator hose getting hot. Watch out for the
engine cooling fan.
By this time, the coolant level inside the coolant
surge tank may be lower. If the level is lower, add
more of the proper mixture to the coolant surge tank
until the level reaches the FULL COLD mark.
5. Then replace the pressure cap. Be sure the
pressure cap is hand-tight and fully seated.
Engine Fan Noise
If your vehicle has a clutched engine cooling fan, when
the clutch is engaged, the fan spins faster to provide
more air to cool the engine. In most everyday driving
conditions, the fan is spinning slower and the clutch is not
fully engaged. This improves fuel economy and reduces
fan noise. Under heavy vehicle loading, trailer towing,
and/or high outside temperatures, the fan speed
increases as the clutch more fully engages, so you may
hear an increase in fan noise. This is normal and should
not be mistaken as the transmission slipping or making
extra shifts. It is merely the cooling system functioning
properly. The fan will slow down when additional cooling
is not required and the clutch disengages.
You may also hear this fan noise when you start the
engine. It will go away as the fan clutch partially
disengages.
If your vehicle has electric cooling fans, you may hear
the fans spinning at low speed during most everyday
driving. The fans may turn off if no cooling is required.
Under heavy vehicle loading, trailer towing, and/or
high outside temperatures, or if you are operating your
air conditioning system, the fans may change to
high speed and you may hear an increase in fan noise.
This is normal and indicates that the cooling system
is functioning properly. The fans will change to low
speed when additional cooling is no longer required.
5-45
Page 549 of 594

Maintenance Footnotes
(Gasoline Engine)
This maintenance section applies to vehicles with a
gasoline engine. If your vehicle has a diesel engine, see
the maintenance schedule section in the DURAMAX
®
Diesel Engine Supplement.
†The U.S. Environmental Protection Agency or the
California Air Resources Board has determined that the
failure to perform this maintenance item will not nullify
the emission warranty or limit recall liability prior to
the completion of the vehicle’s useful life. We, however,
urge that all recommended maintenance services be
performed at the indicated intervals and the
maintenance be recorded.
#Lubricate the front suspension, steering linkage,
transmission shift linkage, and parking brake cable
guides. Control arm ball joints require lubrication
but should not be lubricated unless their temperature is
10°F (−12°C) or higher, or they could be damaged.
Vehicles used under severe commercial operating
conditions require lubrication on a regular basis every
3,000 miles (5 000 km).(a)Visually inspect brake lines and hoses for proper
hook-up, binding, leaks, cracks, cha ng, etc. Inspect
disc brake pads for wear and rotors for surface
condition. Inspect drum brake linings/shoes for wear or
cracks. Inspect other brake parts, including drums,
wheel cylinders, calipers, parking brake, etc.
(b)Visually inspect front and rear suspension and
steering system for damaged, loose or missing parts,
signs of wear or lack of lubrication. Inspect power
steering lines and hoses for proper hook-up, binding,
leaks, cracks, cha ng, etc. Visually check constant
velocity joints, rubber boots, and axle seals for leaks.
(c)Visually inspect hoses and have them replaced
if they are cracked, swollen, or deteriorated. Inspect all
pipes, ttings and clamps; replace with genuine
GM parts as needed. To help ensure proper operation,
a pressure test of the cooling system and pressure
cap and cleaning the outside of the radiator and
air conditioning condenser is recommended at least
once a year.
(d)Visually inspect wiper blades for wear or cracking.
Replace wiper blades that appear worn or damaged
or that streak or miss areas of the windshield.
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Page 550 of 594

(e)Make sure the safety belt reminder light and all your
belts, buckles, latch plates, retractors, and anchorages
are working properly. Look for any other loose or
damaged safety belt system parts. If you see anything
that might keep a safety belt system from doing its
job, have it repaired. Have any torn or frayed safety belts
replaced. Also look for any opened or broken airbag
coverings, and have them repaired or replaced.
The airbag system does not need regular maintenance.
(f)Lubricate all key lock cylinders, body door hinges,
hood latch assembly, secondary latch, pivots, spring
anchor, release pawl, tailgate hinges, tailgate linkage,
tailgate handle pivot points, latch bolt, fuel door
hinge, locks, and folding seat hardware. More frequent
lubrication may be required when exposed to a
corrosive environment. Applying silicone grease on
weatherstrips with a clean cloth will make them
last longer, seal better and not stick or squeak.
(g)Check vent hose at transfer case for kinks and
proper installation.(h)Change automatic transmission uid and lter if the
vehicle Gross Vehicle Weight Rating (GVWR) is
over 8600 lbs or if the vehicle is mainly driven under
one or more of these conditions:
In heavy city traffic where the outside temperature
regularly reaches 90°F (32°C) or higher.
In hilly or mountainous terrain.
When doing frequent trailer towing.
Uses such as found in taxi, police or delivery
service.
(i)Drain, ush, and re ll cooling system. This service
can be complex; you should have your dealer perform
this service. See Engine Coolant on page 5-35 for
what to use. Inspect hoses. Clean radiator, condenser,
pressure cap, and ller neck. Pressure test the
cooling system and pressure cap.
(j)A uid loss in any vehicle system could indicate a
problem. Have the system inspected and repaired and
the uid level checked. Add uid if needed.
6-10