Aeromotive 40 Micron Element for 3/8 NPT Filters 12603 - Commonly the most overlooked component in a fuel system, filter neglect can be the most costly. If not cleaned or replaced regularly, filter elements can become clogged resulting in reduced fuel flow, engine performance and ultimately, fuel pump or even worse, engine damage. By simply replacing and/or cleaning your filter elements regularly, you can avoid costly repairs to your fuel system and ensure peak engine performance. Aeromotive recommends annual inspection and service of filter elements. This includes replacing 10-micron fabric elements and cleaning or replacing 100-micron stainless steel elements. Severe duty applications or newly installed systems may require more frequent maintenance. For Filter P/N's: 12303 and 12353.