Buick 2010 Lacrosse Owner's Manual page 306

See
for information on the
location of the power steering fluid
reservoir.
It is not necessary to regularly
check power steering fluid unless a
leak is suspected in the system or
an unusual noise is heard. A fluid
loss in this system could indicate a
problem. Have the system inspected
and repaired.
Check the level after the vehicle
has been driven for at least
twenty minutes so the fluid is warm.
To check the power steering fluid:
1. Turn the ignition to LOCK/OFF
and let the engine compartment
cool down.
2. Wipe the cap and the top of the
reservoir clean.
3. Unscrew the cap and pull it
straight up.
4. Wipe the dipstick with a
clean rag.
5. Replace the cap and completely
tighten it.
6. Remove the cap again and look
at the fluid level on the dipstick.