An air filter is a device the filters the air entering the engine to remove dust, dirt, and debris. It is sometimes referred to as an air cleaner.
Air filters needs replacing according to the manufacturer's specifications. If is not replaced then dirt and debris could get into the engine and cause premature engine wear.
While most manufacturer factory warranties and extended car warranties doe not cover the cost of replacing the air filter, it is part of the regular maintenance of the vehicle. If something happens to the engine and it is caused by a dirty air filter, then the warranty will be void and the customer will have to pay repair cost.
Synonyms:
air cleaner