GMC Duramax Diesel 2015 Owner's Manual page 86

Warning
The engine oil dipstick handle
may be hot; it could burn you.
Use a towel or glove to touch the
dipstick handle.
2. Pull out the dipstick and wipe it
with a clean paper towel or a
cloth, then push it back in all the
way. Remove it again, keeping
the tip down.
When to Add Engine Oil
If the oil is below the cross-hatched
area at the tip of the dipstick, add
1 L (1 qt) of the recommended oil
and then recheck the level. See
Selecting the Right Engine Oil in
this section for an explanation of
what kind of oil to use. For engine
oil crankcase capacity, see
Capacities and Specifications on
page 12-2.
Caution
Do not add too much oil. Oil
levels above or below the
acceptable operating range
shown on the dipstick are harmful
to the engine. If you find that you
have an oil level above the
operating range, i.e., 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. You should drain
out the excess oil or limit driving
of the vehicle and seek a service
professional to remove the
excess amount of oil.
See Engine Compartment Overview
on page 10-3 for the location of the
engine oil fill cap.
Vehicle Care
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 through.
Selecting the Right Engine Oil
Specification
Oils designated as API CJ-4 are
required for the vehicle. The CJ-4
designation can appear either alone
or in combination with other
American Petroleum Institute (API)
designations, such as API CJ-4/SL.
These letters show API levels of
quality.
10-7