GMC 2004 Yokon Denali Owner's Manual page 438

(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, chafing, 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,
fittings 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, hood latch assembly,
secondary latch, pivots, spring anchor, release pawl, door
hinges, liftgate hinge, liftgate linkage, liftgate handle pivot
6-8
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) 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.
(h) Change automatic transmission fluid and filter 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, flush and refill cooling system. See Engine
Coolant on page 5-24 for what to use. Inspect hoses.
Clean radiator, condenser, pressure cap and filler neck.
Pressure test the cooling system and pressure cap.
(j) A fluid loss in any vehicle system could indicate a
problem. Have the system inspected and repaired and
the fluid level checked. Add fluid if needed.