Chevrolet Low Cab Forward 4500 2019 Series Owner's Manual page 277

276 Service and Maintenance
6. POSITIVE CRANKCASE
VENTILATION (PCV) SYSTEM :
Check that PCV system works
properly. Replace the valve and any
worn, plugged or collapsed hoses
as necessary.
7. SPARK PLUGS : Change every
160 000 km (100,000 miles).
8. SPARK PLUG WIRES : Clean
wires and inspect for burns, cracks
or other damage. Check the wire
boot fit at the coilpack and at the
spark plugs. And replace every
160 000 km (100,000 miles).
9. FUEL TANK, CAP AND LINES :
Inspect the fuel tank, cap and lines
for damage or leaks. Remove fuel
cap, inspect gasket for an even filler
neck imprint, and any damage.
Replace parts as needed.
10. ENGINE ACCESSORY DRIVE
BELT(S) : Inspect belts. Look for
cracks, fraying, wear, and proper
tension. Adjust or replace as
needed, and change every
160 000 km (100,000 miles).
11. EVAPORATIVE CONTROL
SYSTEM (ECS) : Visually check all
fuel and vapor lines and hoses for
proper hookup, routing, and
condition. Check that bowl vent and
purge valves work properly,
if equipped. Replace as needed.
12. SHIELDS AND UNDER HOOD
INSULATION : Inspect shields and
under hood insulation for damage or
looseness. Adjust or replace as
required.
13. AIR INTAKE SYSTEM : Check
the air intake system installation to
see that gaskets are seated
properly and all hose connections,
fasteners, and other components
are tight. Also check to be sure that
the air cleaner housing is properly
seated, that the cover fits tightly,
and the wingnut(s) is/are tight.
Tighten connections and fasteners
or replace damaged parts as
required.
14. THERMOSTATICALLY
CONTROLLED ENGINE COOLING
FAN : With the engine off and below
normal operating temperature,
check to see that the fan can be
rotated by hand on fluid coupling or
viscous drives. Replace as
necessary.
15. AUTOMATIC TRANSMISSION
FLUID :
Check the automatic transmission
fluid level at each engine oil change
and replace fluid every 84 000 km
(52,500 miles). To check the fluid
level, first set the parking brake,
then start the engine in "P" position.
With the regular brakes applied,
move the selector lever through all
the gear positions, ending with "P".