The Ford Motorcraft F4TZ-9S425-A (F4TZ9S425A) is a genuine OEM exhaust manifold bolt engineered specifically for 1994–2003 Ford F-250, F-350, F-450, and F-550 Super Duty and OBS trucks, 2000–2003 Ford Excursions, and 1994.5–2003 Ford E-Series vans equipped with the 7.3L Powerstroke diesel engine. Manufactured to strict Ford engineering standards from high-tensile, heat-treated alloy steel, this factory fastener is designed to withstand extreme exhaust gas thermal cycling without stretching, fatiguing, or shearing. Unlike generic hardware store bolts, genuine Ford 7.3L manifold bolts feature factory-engineered locking thread geometry and a pre-applied anti-corrosion coating that maintains constant clamping force against the cylinder head while preventing the bolt from vibrating loose under heavy engine operation.

Audible ticking or hissing exhaust gas leaks at the cylinder head mating surface, black carbon soot tracking across the exhaust ports, loss of turbocharger drive pressure (boost bleed-off), broken bolt heads caused by thermal fatigue, and snapped hardware during manifold servicing or up-pipe installation are what this genuine replacement bolt eliminates. Because the 7.3L cast-iron exhaust manifolds expand and contract drastically across thousands of heat cycles—especially when towing heavy loads at peak EGTs—reusing aged, stretched, or heat-embrittled factory bolts frequently leads to bolt breakage inside the cylinder head. The Ford F4TZ-9S425-A restores OEM clamping load to seal the manifold tightly against the cylinder head, preventing drive-pressure leaks and ensuring all exhaust energy reaches the turbocharger up-pipes. It is an individual genuine Ford OEM exhaust manifold bolt sold each (8 bolts are needed for an entire manifold; 16 bolts are required to complete both sides of the engine); exhaust manifolds, multi-layer steel exhaust gaskets, and up-pipe hardware are sold separately.

It fits all 1994–1997 Ford OBS and 1999–2003 Ford Super Duty F-250, F-350, F-450, and F-550 trucks, 2000–2003 Ford Excursions, and 1994.5–2003 Ford E-250, E-350, and E-450 Econoline vans equipped with the 7.3L Powerstroke turbo diesel engine (also compatible with Navistar T444E applications).

Fitment

• 1994–1997 Ford F-250 / F-350 7.3L Powerstroke Turbo Diesel (OBS)
• 1999–2003 Ford F-250 / F-350 / F-450 / F-550 Super Duty 7.3L Powerstroke Turbo Diesel
• 2000–2003 Ford Excursion 7.3L Powerstroke Turbo Diesel
• 1994.5–2003 Ford E-250 / E-350 / E-450 Econoline Van 7.3L Powerstroke Turbo Diesel
• Navistar T444E 7.3L Diesel Engine
• Genuine Ford OEM replacement fastener guarantees factory thread engagement and clamping force
• High-strength, heat-treated alloy steel construction resists thermal stretching and fatigue
• Specialized locking thread design prevents fastener from backing out under heavy vibration
• Direct replacement for broken, rusted, or stretched original manifold hardware
• Direct replacement for OEM Ford part numbers F4TZ-9S425-A, F4TZ9S425A, and Navistar 1823180C1
• Sold individually (8 required for an entire manifold; 16 required per engine)
• Backed by Ford Motorcraft’s 2-Year, Unlimited-Mileage Warranty

Park the vehicle on a level surface, disconnect both negative battery cables, and remove the front inner fender liner to gain direct, straight-on access to the cylinder head exhaust ports. Apply a high-performance penetrating oil to all existing exhaust manifold bolt heads and threads multiple times over several hours prior to removal to reduce the risk of shearing seized fasteners in the cylinder head. Unbolt the rear manifold collector flange from the turbocharger up-pipe collector, then carefully loosen and remove the original manifold bolts using a 6-point socket (avoid using air impacts to prevent snapping aged bolts). Remove the exhaust manifold and scrape the cylinder head mating surface and manifold face with a wire brush or scraper until completely flat, bare, and free of carbon soot and rust scale. Run an M10 x 1.5 thread chase tap into each cylinder head bolt hole and blow out all debris with compressed air to guarantee accurate torque readings. Position the exhaust manifold (along with new manifold gaskets if utilizing aftermarket multi-layer steel gaskets) against the cylinder head. Apply a light coat of high-temperature anti-seize lubricant or assembly lube to the new Ford F4TZ-9S425-A bolt threads and install all 8 bolts finger-tight. Working in an alternating spiral sequence from the center cylinders outward toward the ends, torque the bolts in two stages: first stage to 25 ft-lbs, and a final torque stage to 35 ft-lbs (47 Nm). Reconnect and torque the turbocharger up-pipe collector bolts, reinstall the inner fender liner, reconnect both negative battery cables, and start the engine to verify zero exhaust drive-pressure leaks around the manifold flanges.