The Alliant Power AP63452 is a 100% brand-new, OEM-grade engine oil cooler tube bundle core 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. Mounted horizontally along the driver-side lower engine block between the factory front and rear cast-aluminum headers, this heavy-duty multi-tube heat exchanger core transfers thermal energy from high-pressure engine oil directly into circulating engine coolant. Built to meet or exceed original equipment specifications, Alliant Power constructs this replacement core with heavy-duty brazed internal tube assemblies and precision-machined sealing lands designed to withstand high hydraulic oil spikes and severe thermal cycling without cracking or fatiguing.

Catastrophic engine oil and coolant cross-contamination, thick black oil sludge pushing into the cooling system degas bottle, milkshake-like emulsified coolant inside the radiator, elevated engine oil temperatures while hauling heavy payloads, and cracked internal tube bundles caused by age and corrosion are what this cooler core cures. Because base engine oil pressure operates between 40 and 70+ PSI while the cooling system runs at approximately 16 PSI, any internal rupture in the tube bundle immediately forces pressurized engine oil into the coolant circuit, rapidly coating the radiator and heater core in sludge and leading to engine overheating. The Alliant Power AP63452 replaces the compromised internal tube bundle with a brand-new, factory-spec heat exchanger core to restore thermal control and fluid isolation between the lubrication and cooling circuits. It is an OEM-replacement bare center oil cooler tube bundle; the front header (F4TZ-6881-B), rear filter header (F81Z-6881-BA), mounting gaskets, and internal silicone O-ring kits (Alliant AP0004) 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 Ford F-650/F-750 medium-duty trucks and 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
• 2000–2003 Ford F-650 / F-750 7.3L Diesel
• 100% brand-new OEM-replacement engine oil cooler tube bundle core
• Precision-brazed internal multi-tube construction ensures optimal heat exchange and durability
• Precision-machined tube ends ensure leak-free O-ring sealing inside factory cast headers
• Permanently cures oil-into-coolant fluid cross-contamination and cooling system sludging
• Direct replacement for OEM Ford part numbers 1C3Z-6A642-AA, F4TZ-6A642-A, and Navistar 1815904C2, 1818378C94
• Driver-side lower engine block mounting location
• Backed by Alliant Power’s 24-Month, Unlimited-Mileage Warranty

Position a large drain catch pan underneath the driver side of the engine, open the radiator drain valve to evacuate all engine coolant, spin off and discard the engine oil filter, and drain the engine oil from the crankcase. Unbolt the three rear oil filter header mounting bolts and the front header-to-block mounting bolts, then extract the complete oil cooler assembly from beneath the chassis. Place the assembly onto a sturdy workbench and use a dead-blow mallet or wooden block to separate both factory cast-aluminum headers from the old tube bundle (inspect the internal casting bores for severe pitting or cracks). Thoroughly clean the inner receiver bores of both cast headers using a Scotch-Brite pad and brake cleaner to remove all residual rubber, oxidation, and road grime. Generously coat new silicone O-rings (Alliant AP0004 or Mahle GS33545) and the tube lands of the new Alliant Power AP63452 with clean engine oil or petroleum jelly, rolling the O-rings into place on both ends of the bundle core. Using a bench vise, hydraulic press, or heavy-duty bar clamps, press each cast header straight, square, and evenly onto the new tube bundle until fully seated, verifying correct rotational alignment relative to the engine block mounting pads. Clean the engine block mounting pads until completely flat and oil-free, place new composite block gaskets into position dry (do not apply RTV silicone), and mount the assembly to the block. Torque all front and rear header-to-block bolts in an alternating sequence to 18 ft-lbs (24 Nm). Install a fresh oil filter, fill the crankcase with 15W-40 diesel oil, thoroughly flush the cooling system if prior oil contamination occurred, refill with a fresh 50/50 diesel coolant mix, and run the engine up to operating temperature to inspect for leaks.