4.1. A Unfasten the spring clips and unscrew the wing nut...
4.1B... remove the air filter cover...
2. Lift the element.
3. Wipe the inside of the air filter housing and cover.
4. If a genuine Nissan element is used, cleaning is not required between the specified replacement intervals. Non-genuine elements can be cleaned as follows.
5. Knock out the dust from the element, then blow out the remaining dust from inside the element with compressed air.
6. Install the element and air cleaner cover. Secure the cover, tighten the wing nut until it contacts the metal washer, then tighten the nut four full turns. Do not overtighten the nut (photo). Finally, install the spring clips.
4.6 Tighten the wing nut as described in the text