Magnaflow 2004 Buick Rainier 5.3L Direct Fit Converter

MagnaFlow builds well-known catalytic converters, and the 4451172 covers a group of 2004 GM mid-size SUVs that share the same exhaust platform: the Buick Rainier, Chevrolet Trailblazer EXT, GMC Envoy XL, and Isuzu Ascender. All four vehicles use the same exhaust routing for this converter position, which is why one part number covers the group.

This direct-fit converter is constructed from 16-gauge 409 stainless steel tubing with mandrel bends that match the factory pipe geometry. MagnaFlow's 3D scanning process during development ensures the flanges, hangers, and pipe path align with the OE setup. The spun body uses a single laser fusion weld, and 308 stainless steel MIG welds secure the pipe joints. A Torca AccuSeal exhaust clamp is included, providing 360-degree evenly distributed clamping force that prevents pipe distortion during installation.

In the box you also get one crush ring gasket and one donut gasket, so every sealing point gets fresh hardware. Installation is straightforward with no cutting or welding required. This converter meets CARB requirements and is legal in all 50 states. Verify your vehicle's Executive Order number and Engine Family Number match this converter's CARB EO.