GMC 2007 Sierra 1500 Pickup Owner's Manual page 487

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 will 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 609.
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 480 for the
location of the engine
oil fill cap.
487