Magnaflow 04-05 Ford Freestar 3.9L Direct Fit Converter

If the check engine light has come on in your 2004-2005 Ford Freestar or Mercury Monterey with the 3.9L engine, a failing catalytic converter is one of the most common causes. This MagnaFlow direct-fit replacement (part number 4551079) bolts in using the original mounting points with no cutting or welding required, and it meets California Air Resources Board (CARB) standards for legal use in all 50 states.

MagnaFlow builds this converter with 16-gauge 409 stainless steel tubing for corrosion resistance and mandrel-bent piping that replicates the OE design geometry. The single laser fusion weld reduces the chance of exhaust leaks, and the spun body design keeps the converter compact for better thermal efficiency. Gaskets and hardware come in the box, so you are not stuck reusing corroded factory fasteners.

This converter interchanges with OE parts 3F2Z-5F250-AA, 3F2Z-5F250-EA, and 3F2Z-5F250-EB, making it a straightforward match for the factory part. MagnaFlow uses 3D scanning during development to match the OE fitment precisely, so the converter drops into the same location and connects to the same exhaust hangers as the original. If you need a CARB-compliant catalytic converter for your Freestar or Monterey that installs without a trip to the exhaust shop, this is a direct replacement.