Assuming you have Duratec on your Contour, it's right under the upper intake manifold (UIM for short) and the throttle body (TB for short). It'll probably be easiest if you take the air filter housing along with the stock air supply tube out to get to the PCV valve. It's possible to take change the valve without taking those other stuff off, but the rubber hose might be a little sticky and you risk the chance of dropping the valve.