GMC 2003 C4C042 Owner's Manual page 281

Engine Oil (Caterpillar
Diesel Engines)
R
See your Caterpillar Operation & Maintenance Manual
for information on oil quality and viscosities as well as
the temperature range chart.
Engine Oil (DURAMAX
Checking Engine Oil
It's a good idea to check your engine oil level every time
you get fuel.
R
t
Diesel)
The engine oil dipstick is
located in the engine
compartment on the driver's
side of the vehicle.
In order to get an accurate
reading, the oil must be
warm (at normal operating
temperature) and the vehicle
must be on level ground.
Turn off the engine and give the oil at least five minutes
to drain back into the oil pan. With a cool engine, allow
30 minutes. If you don't, the oil dipstick might not show
the actual level.
Pull out the dipstick and clean it with a paper towel or a
cloth, then push it back in all the way. Remove it again,
keeping the tip down.
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