GMC Sierra Classic 2007 Owner's Manual page 483

When to Add Engine Oil
All Except 8.1L Engine
8.1L Engine
If the oil is below the cross-hatched area at the
tip of the dipstick, you need to add at least
one quart/liter of oil. But you must use the right
kind. This section explains what kind of oil to use.
For engine oil crankcase capacity, see Capacities
and Specifications on page 605.
Notice: Do not add too much oil. If the engine
has so much oil that the oil level gets above
the cross-hatched area that shows the
proper operating range, the engine could
be damaged.
Be sure to add enough oil to put the level
somewhere in the proper operating range.
Push the dipstick all the way back in when
you are through.
See Engine
Compartment Overview
on page 476 for the
location of the engine
oil fill cap.
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