Saturn 2007 AURA Green Line Hybrid Owner's Manual page 266

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 351.
Notice: Do not add too much oil. If the engine
has so much oil that the oil level gets above
the upper mark that shows the proper
operating range, the engine could be damaged.
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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 264 for the
location of the engine oil
fill cap.