2004 GMC SONOMA radiator cap

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 arrow on the pressure cap lines up like this.
5-34

99,000 Miles (165 000 km)
❑Change engine oil and filter (or every 3 months,
whichever occurs first).An Emission Control Service.
❑Lubricate chassis components (or every 3 months,
whichever occurs first).(See footnote #.)
❑Check rear/front axle fluid level and add fluid as
needed. Check constant velocity joints and axle seals
for leaking.(See footnote **.)
100,000 Miles (166 000 km)
❑Inspect spark plug wires.An Emission Control
Service.
❑Replace spark plugs.An Emission Control Service.
❑If you have not used your vehicle under severe
service conditions listed previously and, therefore,
have not changed your automatic transmission fluid,
change both the fluid and filter.
❑Inspect Positive Crankcase Ventilation (PCV) valve.
An Emission Control Service.
150,000 Miles (240 000 km)
❑Drain, flush and refill cooling system (or every
60 months since last service, whichever occurs first).
SeeEngine Coolant on page 5-23for what to use.
Inspect hoses. Clean radiator, condenser, pressure
cap and neck. Pressure test cooling system and
pressure cap.An Emission Control Service.
❑Inspect engine accessory drive belt.An Emission
Control Service.
Long Trip/Highway Scheduled
Maintenance
The services shown in this schedule up to 100,000 miles
(166 000 km) should be repeated after 100,000 miles
(166 000 km) at the same intervals for the life of
this vehicle. The services shown at 150,000 miles
(240 000 km) should be repeated at the same interval
after 150,000 miles (240 000 km) for the life of this
vehicle.
SeePart B: Owner Checks and Services on page 6-25
andPart C: Periodic Maintenance Inspections on
page 6-30.
Footnotes
†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, ball joints, steering
linkage, parking brake cable guides, propshaft splines,
universal joints, constant velocity joint and brake
pedal springs.
6-17

97,500 Miles (162 500 km)
❑Change engine oil and filter (or every 12 months,
whichever occurs first).An Emission Control
Service.
❑Lubricate chassis components (or every 12 months,
whichever occurs first).(See footnote #.)
❑Check rear/front axle fluid level and add fluid as
needed. Check constant velocity joints and axle seals
for leaking.(See footnote **.)
❑Rotate tires. SeeTire Inspection and Rotation on
page 5-68for proper rotation pattern and additional
information.(See footnote +.)
100,000 Miles (166 000 km)
❑Inspect spark plug wires.An Emission Control
Service.
❑Replace spark plugs.An Emission Control Service.
❑If you have not used your vehicle under severe
service conditions listed previously and, therefore,
have not changed your automatic transmission fluid,
change both the fluid and filter.
❑Inspect Positive Crankcase Ventilation (PCV) valve.
An Emission Control Service.
150,000 Miles (240 000 km)
❑Drain, flush and refill cooling system (or every
60 months since last service, whichever occurs first).
SeeEngine Coolant on page 5-23for what to use.
Inspect hoses. Clean radiator, condenser, pressure
cap and neck. Pressure test the cooling system
and pressure cap.An Emission Control Service.
❑Inspect engine accessory drive belt.An Emission
Control Service.
6-24

Part C: Periodic Maintenance
Inspections
Listed in this part are inspections and services which
should be performed at least twice a year (for instance,
each spring and fall).You should let your dealer’s
service department do these jobs. Make sure any
necessary repairs are completed at once.
Proper procedures to perform these services may be
found in a service manual. SeeService Publications
Ordering Information on page 7-11.
Steering, Suspension and Front
Drive Axle Boot and Seal Inspection
Inspect the front and rear suspension and steering
system for damaged, loose or missing parts, signs of
wear or lack of lubrication. Inspect the power steering
lines and hoses for proper hook-up, binding, leaks,
cracks, chafing, etc. Clean and then inspect the drive
axle boot seals for damage, tears or leakage. Replace
seals if necessary.
Exhaust System Inspection
Inspect the complete exhaust system. Inspect the body
near the exhaust system. Look for broken, damaged,
missing or out-of-position parts as well as open seams,
holes, loose connections or other conditions which
could cause a heat build-up in the floor pan or could let
exhaust fumes into the vehicle. SeeEngine Exhaust
on page 2-29.
Fuel System Inspection
Inspect the complete fuel system for damage or leaks.
Engine Cooling System Inspection
Inspect the hoses and have them replaced if they
are cracked, swollen or deteriorated. Inspect all pipes,
fittings and clamps; replace as needed. Clean the
outside of the radiator and air conditioning condenser.
To help ensure proper operation, a pressure test of
the cooling system and pressure cap is recommended
at least once a year.
6-30

Parking Brake and Automatic Transmission
Park (P) Mechanism Check...........................6-29
Parking on Hills..............................................4-62
Part A - Scheduled Maintenance Services............ 6-4
Part B - Owner Checks and Services................6-25
Part C - Periodic Maintenance Inspections..........6-30
Part D - Recommended Fluids and Lubricants....6-32
Part E - Maintenance Record...........................6-36
Passing.................................................4-11, 4-61
Passlock
®......................................................2-16
Payload.........................................................4-51
Pickup Conversion to Chassis Cab....................4-54
Plan Ahead When Possible................................ 7-7
Playing a Cassette Tape..................................3-54
Playing a CD.................................3-47, 3-57, 3-68
Playing a Specific Loaded CD..........................3-69
Playing the Radio...................3-36, 3-40, 3-49, 3-60
Power
Accessory Outlets........................................3-16
Door Locks.................................................. 2-8
Electrical System.........................................5-95
Lumbar Controls........................................... 1-4
Seat............................................................ 1-3
Steering Fluid.............................................5-35
Windows....................................................2-13
Power Steering................................................ 4-9
Programmable Automatic Door Locks.................. 2-8
Q
Questions and Answers About Safety Belts.........1-12
R
Radiator Pressure Cap....................................5-26
Radio Data System (RDS)...............3-39, 3-52, 3-59
Radio Messages.....................3-38, 3-44, 3-54, 3-65
Radios..........................................................3-35
AM-FM Radio.............................................3-36
Care of Your Cassette Tape Player................3-74
Care of Your CD Player...............................3-76
Care of Your CDs........................................3-75
Radio with Cassette and CD.........................3-49
Radio with CD............................................3-39
Radio with Six-Disc CD................................3-59
Setting the Time for Radios with Radio
Data Systems (RDS)................................3-36
Setting the Time for Radios without
Radio Data Systems (RDS).......................3-35
Theft-Deterrent............................................3-73
Understanding Reception..............................3-74
RDS Messages..............................3-43, 3-53, 3-64
11