Oldsmobile ALERO 2001 Owner's Manual page 254

2.4L L4 Engine
The 2.4L L4 engine oil fill cap is located on the
passenger's side of the engine compartment on the engine.
6-16
3400 V6 Engine
The 3400 V6 engine oil fill cap is on the front of the
engine, behind the radiator.
See "Engine Compartment Overview" in the Index for
more information on location.
Be sure to fill it enough to put the level somewhere in
the proper operating range. Push the dipstick all the way
back in when you're through.