The engine air filter is located above the engine and filters the incoming combustion air for the engine. These should be checked every oil change and depending on where and how you drive they should be replaced about every other to every third oil change or else bad gas mileage and poor engine performace will occur.
The cabin air filter removes dust and pollen from the air entering the interior of the car through the heating and air conditioning system when the control is set to "fresh air" or "outside air". This is less critical but will eventually be clogged and will need changing.
Also normally they are different styles of air filter so a different type for each one, your owners manual should tell you the types.
There is no Power Steering Filter on a 2002 Subaru Legacy/Outback.
The Subaru Outback fuel filter is located inside of the fuel tank. Changing the fuel filter can be very costly and time-consuming.
It's on the right front side of the engine and accessible from under the car.
Bottom of the engine near the front. It points straight down.
where would you find out if the Air Conditioner filter is blocked on a 2005 Subaru Outback
On the 2010 Subaru Outback, the oil filter is located on the underside of the engine, towards the front. You can access it by lifting the vehicle and removing the plastic engine cover if equipped. It's positioned near the oil pan and may be a bit tight to reach, so using an oil filter wrench can help during removal and installation.
Top front of engine, beside Oil Pump, right above Oil Filter.
I found no mention of a power steering filter in the owner's manual or in the service manual for Outback.
Top front of engine, beside Oil Pump, right above Oil Filter.
The oil capacity for a 2004 Subaru Outback with a 2.5L engine is approximately 4.5 quarts (or about 4.3 liters) when using a filter change. For the 3.0L engine, the capacity is around 6.9 quarts (or about 6.5 liters) with a filter change. Always refer to the owner's manual for the most accurate specifications and recommendations for your specific vehicle model.
There should be a black box located on the left, inside your engine bay, mine's made out of plastic, your air filter should be located in there.
http://www.cars101.com/subaru/airfiltration.html#00-04legacy