Chevrolet 1998 C/K Full-Size Pickup Owner's Manual page 376

Maintenance Schedule
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Short TripKity Intervals
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Gasoline Engines
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Every 100,000 Miles (166 000 km): Spark Plug Wire
Inspection. Spark Plug Replacement. Automatic
Transmission Service (normal conditions). Positive
Crankcase Ventilation (PCV) Valve Inspection.
Every 150,000 Miles (240 000 km): Cooling System
Service (or every 60 months, whichever occurs first).
These intervals only summarize maintenance services.
Be sure to follow the complete maintenance schedule on
the following pages.
Long TripBghway Definition
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Gasoline Engines
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Follow this maintenance schedule only if none of the
conditions from the Short Trip/City Maintenance
Schedule is true. Do not use this schedule if the vehicle
is used for trailer towing, driven in a dusty area or used
off paved roads. Use the Short Trip/City schedule for
these conditions.
Driving a vehicle with amfully warmed engine under
h.ighway conditions causes engine oil to break
down slower:
7-6