GMC 2007 Envoy - Manual (Page 395)

If the oil is below the L mark for the L6 engine or
the cross-hatched area at the tip of the dipstick
for the V8 engine, 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 502.
Notice: Do not add too much oil. If the engine
has so much oil that the oil level gets above
the cross-hatched area (F) that shows the
proper operating range for the L6 engine or
above the cross-hatched area for the
V8 engine, the engine could be damaged.
See Engine
Compartment Overview
on page 390 for the
location of the engine oil
fill cap.
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.
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