2004 GMC SIERRA DENALI radiator cap

Checking Coolant
The coolant surge tank is
located in the engine
compartment on the
passenger's side of the
vehicle. See
Engine
Compartment Overview on
page 5-10
for more
information on location.
{CAUTION:
Turning the surge tank pressure cap when the
engine and radiator are hot can allow steam
and scalding liquids to blow out and burn you
badly. Never turn the surge tank pressure
cap Ð even a little Ð when the engine and
radiator are hot.
The vehicle must be on a level surface. When your
engine is cold, the coolant level should be at the FULL
COLD mark.
If your vehicle is equipped with a low coolant sensor,
and the LOW COOLANT LEVEL message comes
on and stays on, it means you're low on engine coolant.
See ªLow Coolant Levelº under
DIC Warnings and
Messages on page 3-57.
5-23

Cooling System
When you decide it's safe to lift the hood, here's what
you'll see:
A. Coolant Surge Tank
B. Coolant Surge Tank Pressure Cap
C. Engine FanIf the coolant inside the coolant surge tank is boiling,
don't do anything else until it cools down. The vehicle
should be parked on a level surface.
The coolant level should
be at or above the FULL
COLD mark. If it isn't,
you may have a leak at the
pressure cap or in the
radiator hoses, heater
hoses, radiator, water
pump or somewhere else
in the cooling system.
5-28

{CAUTION:
Adding only plain water to your cooling
system can be dangerous. Plain water, or
some other liquid such as 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 would not get the overheat warning.
Your engine could catch ®re and you or others
could be burned. Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
žcoolant.
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. Do not spill coolant on a hot engine.
1. Park the vehicle on a
level surface. You can
remove the coolant
surge tank pressure
cap when the cooling
system, including
the coolant surge tank
pressure cap and
upper radiator hose, is
no longer hot.
Turn the pressure cap slowly counterclockwise
(left) about one full turn. If you hear a hiss, wait for
that to stop. A hiss means there is still some
pressure left.
5-31

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.
5-33

Maintenance Footnotes
²The 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, ball joints, steering
linkage, transmission shift linkage and parking
brake cable guides. Ball joints should not be lubricated
unless their temperature is 10ÉF (-12ÉC) or higher,
or they could be damaged.
(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 other brake parts, including 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 blade inserts that appear worn or damaged
or that streak or miss areas of the windshield.
(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 air bag
coverings, and have them repaired or replaced. (The air
bag 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, tailgatelinkage,
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.
6-8

(g)Add ¯uid as needed. A ¯uid loss could indicate a
problem; repair as needed. Check vent hose at transfer
case for kinks and proper installation.
(h)Change automatic transmission ¯uid and ®lter if the
vehicle is mainly driven under one or more of these
conditions:
þIn heavy city traffic where the outside temperature
regularly reaches 90ÉF (32ÉC) or higher.
þIn hilly or mountainous terrain.
þWhen doing frequent trailer towing.
þUses such as found in taxi, police or delivery
service.
(i)Drain, ¯ush and re®ll cooling system. See Engine
Coolant on page 5-21for 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.
(k)Inspect system. Check all fuel and vapor lines and
hoses for proper hook-up, routing and condition.
Check that the purge valve works properly (if equipped).
Replace as needed.
Owner Checks and Services
These owner checks and services should be performed
at the intervals speci®ed to help ensure the safety,
dependability and emission control performance of your
vehicle. Your GM Goodwrench dealer can assist you
with these checks and services.
Be sure any necessary repairs are completed at once.
Whenever any ¯uids or lubricants are added to your
vehicle, make sure they are the proper ones, as shown
in
Recommended Fluids and Lubricants on page 6-13.
At Each Fuel Fill
It is important to perform these underhood checks at
each fuel ®ll.
Engine Oil Level Check
Check the engine oil level and add the proper oil if
necessary. SeeEngine Oil on page 5-11for further
details.
Notice:It is important to check your oil regularly
and keep it at the proper level. Failure to keep your
engine oil at the proper level can cause damage
to your engine not covered by your warranty.
6-9