The Ford Motorcraft F81Z-9431-AA is a genuine OEM driver-side (left-hand) exhaust manifold engineered specifically for 1999–2003 Ford F-250, F-350, F-450, and F-550 Super Duty trucks and 2000–2003 Ford Excursions equipped with the 7.3L Powerstroke diesel engine. Cast from high-strength, heavy-duty ductile iron directly to original Ford factory engineering specifications, this OEM manifold is designed to withstand severe thermal expansion, extreme exhaust gas temperatures (EGTs), and continuous diesel engine harmonics without warping, distorting, or cracking. It features precision-machined port faces to create a flush seal against the cylinder head, as well as a factory-flanged rear discharge port engineered to mate to the driver-side turbocharger up-pipe collector.

Ticking or hissing exhaust leaks from the driver side of the engine bay, telltale black carbon soot staining along the cylinder head ports, cracked casting runners caused by thermal cycling, warped sealing flanges that pull away from the head, and low boost or sluggish turbo spool resulting from lost exhaust drive pressure are what this genuine manifold cures. Under heavy towing and high EGT loads, aged cast manifolds can develop stress fractures or bow across the mounting plane, allowing exhaust drive pressure to escape before reaching the turbine wheel. The genuine Ford F81Z-9431-AA delivers exact factory dimensional accuracy, providing uncompromised clearance around the steering shaft, oil cooler bundle, and driver-side frame rail. It is an authentic Ford OEM bare driver-side cast-iron exhaust manifold; manifold mounting bolts (F4TZ-9S425-A), multi-layer steel exhaust gaskets, and up-pipe hardware are sold separately.

It fits all 1999–2003 Ford Super Duty F-250, F-350, F-450, and F-550 trucks and 2000–2003 Ford Excursions equipped with the 7.3L Powerstroke turbo diesel engine (driver/left-hand side only; fits both Early 1999 and Late 1999–2003 models).

Fitment

• 1999–2003 Ford F-250 Super Duty 7.3L Powerstroke Turbo Diesel (Early 1999 & Late 1999–2003)
• 1999–2003 Ford F-350 Super Duty 7.3L Powerstroke Turbo Diesel
• 1999–2003 Ford F-450 / F-550 Super Duty 7.3L Powerstroke Turbo Diesel
• 2000–2003 Ford Excursion 7.3L Powerstroke Turbo Diesel
• Genuine Ford OEM casting ensures exact factory fitment, bolt pattern, and port alignment
• Heavy-duty ductile cast-iron construction resists heat distortion, runner cracking, and fatigue
• Eliminates exhaust drive-pressure leaks to restore maximum turbo boost and lower EGTs
• Precision-machined port sealing surfaces and up-pipe flange connection
• Engineered exclusively for the driver-side (left-hand) cylinder bank
• Direct replacement for original factory part number F81Z-9431-AA
• Backed by Ford Motorcraft’s 2-Year, Unlimited-Mileage Warranty

Park the truck on a level surface, set the emergency brake, and disconnect both negative battery cables. Remove the driver-side front wheel and detach the inner plastic fender splash shield to gain direct, straight-on access to the exhaust ports and manifold fasteners. Spray a high-quality penetrating oil generously onto all eight manifold-to-head bolts and the two rear up-pipe collector flange fasteners multiple times prior to removal to reduce the risk of shearing seized hardware in the cylinder head. Unbolt the two bolts securing the driver-side turbo up-pipe collector to the rear manifold flange. Using a 6-point socket and breaker bar, carefully loosen and remove the eight factory exhaust manifold bolts (avoid air impacts to prevent snapping heat-stressed fasteners). Remove the old manifold and thoroughly clean the cylinder head exhaust port faces with a wire brush or scraper until the cast iron is flat, smooth, and free of carbon soot and rust scale. Run an M10 x 1.5 thread-chasing tap through each cylinder head bolt hole and blow out all debris with compressed air to guarantee proper torque specs. Position the new Ford F81Z-9431-AA manifold against the cylinder head (with an approved multi-layer steel gasket if preferred). Apply high-temperature anti-seize to the threads of new Ford manifold bolts (F4TZ-9S425-A), thread all eight bolts in finger-tight, and torque them in an alternating spiral sequence from the center ports outward in two stages: first to 25 ft-lbs, then final torque to 35 ft-lbs (47 Nm). Reattach the turbo up-pipe collector flange with fresh hardware and torque to 35 ft-lbs. Reinstall the inner wheel well liner and front wheel, reconnect both negative battery cables, and start the engine to confirm a complete, leak-free exhaust seal.