2003 Buick Century Owner's Manual - Page 252

Power Steering Fluid L 11. Then replace the pressure cap. At any time during this procedure if coolant begins to flow out of the filler neck, reinstall the pressure cap. Be sure the arrow on the pressure cap lines up like this. 12. Check the coolant in the recovery tank. The level in the coolant recovery tank should be at the HOT mark when the engine is hot or at the COLD mark when the engine is cold. The power steering fluid reservoir is located on the passenger's side of the vehicle at the back of the engine compartment, and can be identified by the above graphic on the cap. 5-35