The engine housing for air filters sits on the left-front side of the compartment. For 350Z owners: loosen and unclip two supporting pieces to remove both filter cartridge and filter. Check the filter element out front. Switch the dirty one, but you can use same filter again if dusting is normal by blowing air through the back and front of the filter. You cannot clean a pleated paper type filter using water or oil - no amount of cleaning will be effective enough. Throw it away when it's too dirty to clean. You must be careful not to let anything fall into the housing while you're working on the cover. Driving with the air filter off damages the engine and could cause a fire, make sure you don't do this. Clean up the air filter's housing outside, then put the new filter right where it fits. Reinstall by simply reversing the steps you used to take the cover off.