Q: I have an air filter with a paper inside and a foam piece around the outside. Do I need to change both every year?
A: No. The outside foam pre-cleaner is designed to catch most of the larger dust and debris particles, while the paper filter is the last defense for the engine. Most foam filters are designed to be washed out with soap and water (rather than needing to be replaced each time). After you wash out the foam, let it air-dry completely and then squeeze a few drops of motor oil through the filter. This will help trap dust as it enters the filter. The inside paper filter cannot be cleaned and needs to be replaced when the grooves become dirty (hold it up to light – if you can’t see light all the way through, it’s time for a new one).