To be certain, it's best to:
* Consult your owner's manual: This is the most reliable source for the specific location on your vehicle.
* Look for a cap with a power steering symbol: The reservoir cap usually has a symbol indicating its function.
* Check online resources: Sites like repair manuals (like Chilton or Haynes) or forums dedicated to Buick Park Avenues may have pictures or descriptions of the location.
Be cautious when working in the engine compartment; allow the engine to cool completely before checking fluid levels.