GMC 2018 Acadia Denali Owner's Manual page 334

High use commercial vehicles
such as courier delivery
vehicles, private security patrol
vehicles or any vehicles that
operate on a 24 hour basis.
Any vehicle consistently
operated in a high sand or
dust environment such as
those used on oil pipelines
and similar applications.
Vehicles that are regularly used
for short trips of 6 km/3.7 mi
or less
If your vehicle has an Oil Life
Indicator, the indicator will show
you when to change the oil and
filter. Under severe conditions
the indicator may come on
before 10 000 km/6,000 mi. The
indicator won't detect dust in the
oil, so if you drive in a dusty
area you may have to change
the oil and filter sooner than
every 10 000 km/6,000 mi.
Note: All vehicles with
rear-wheel drive change
driveline axle oil every
30 000 km/19,000 mi if vehicle is
used for towing purposes.
* Footnote: Under extreme
driving conditions listed above, it
may be necessary to replace
your spark plugs at more
frequent intervals. For further
assistance in determining the
most suitable service
maintenance intervals for your
vehicle, please contact your
authorized GM Dealer.
Additional Required Services
Severe Service
Every 60 000 km/38,000 mi
Inspect evaporative control
system. Visually check all fuel
and vapor lines and hoses for
proper attachment, connection,
routing, and condition.
Visually inspect accessory drive
belts. Or every three years,
whichever comes first. Inspect
for fraying, excessive cracking,
or damage; replace, if needed.
Every 72 000 km/45,000 mi
Change automatic transmission
fluid.
Service and Maintenance
Every 80 000 km/50,000 mi
Replace spark plugs. Inspect
spark plug wires.
Every 240 000 km/150,000 mi
Drain and fill engine cooling
system. Or every five years,
whichever comes first. See
Cooling System 0 268.
333