The DD15 fuel filter typically requires a 36mm socket or filter wrench for the primary filter housing cap, and a 1-3/16 inch (or 30mm) socket for the secondary spin-on housing. The primary uses a plastic threaded cap that turns counter-clockwise to open from the top. Some Cascadia configurations have a tighter 32mm cap depending on housing generation. Always check the cap size against the filter housing label before ordering tools; Detroit revised the housing across model years. A standard fuel filter wrench (band-style or strap-style) works on the secondary spin-on if a socket is not handy. For pre-priming after the swap, the DD15 has an electric prime pump that runs from the dash; no manual hand-prime needed on most configurations. The plastic cap is the failure point if over-torqued, so do not force it past spec.
Browse the Detroit DD15 / DD13 / DD16 Filters collection →