If you are taking an ASE Test like the G1, You may run across a question like this:
When an air filter is inspected, what are the most important criteria the technician needs to pay attention to:
B) Amount of contaminates on the filter media
D) Number of cylinders
E) A & B
The answer is E!
Air filters keep dirt and abrasive particles out of the engine. A good-quality air filter will trap about 98 percent or more of the particles that can cause trouble inside an engine. As the filter media becomes saturated with dirt, its efficiency actually increases. But, as the filter becomes clogged with more and more dirt, it also becomes more restrictive to airflow.
The greater the pressure drop across the filter, the more it hurts performance and fuel economy.Ideally, an air filter will be replaced before it causes a restriction in airflow. Whether or not an air filter goes 30,000 miles or 50,000 miles before it needs to be replaced depends on driving conditions and how much dirt the filter has ingested over those miles. Driving on dusty rural gravel roads is a lot different than suburban or city driving. Air filters need to be inspected regularly and changed more on an “as needed” basis than the mileage on the odometer.Location of the filter under the hood or the number of cylinders, are not criteria that comes in to play when replacing filters. This video is sponsored by FRAM.