GMC 2007 Acadia Owner's Manual page 398

When to Add Engine Oil
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 497.
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.
398
Be sure to add enough oil to put the level
somewhere in the proper operating range in the
cross-hatched area. Push the dipstick all the
way back in when you are through.
See Engine
Compartment Overview
on page 396 for the
location of the engine
oil fill cap.