When it's time for you to change the oil in your Ford Focus, you will also need to change the oil filter. To do that, you will need to know where the oil filter is and what it looks like. But locating the oil filter is easy. All you'll really need is flashlight and a basic idea of what you're looking for.
Lift the front of your Focus with a hydraulic jack. Make sure that the wheels are at least three inches off the ground.
Slide on your back under the front of your Focus while holding a flashlight.
Turn on the flashlight. Look up when you are near the centre of the engine compartment. Above the bolt that holds the oil in your oil pan, there is a cylinder roughly the size of a large soup can. This is the oil filter, which is often white but comes in other colours as well.