2004 Buick Century Owner's Manual - Page 247

Power Steering Fluid 10. 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. 11. 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 at the back of the engine compartment, on the passenger's side of the vehicle. See Engine Compartment Overview on page 5-12 for reservoir location. 5-35