The Dieselsite DS_LPOP73 is an upgraded, high-volume Low Pressure Oil Pump (LPOP) 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. Engineered as an advanced billet and steel solution over standard cast replacement units, this high-output pump increases base oil displacement by over 8% across the entire RPM band. By utilizing an optimized, precision-machined internal gerotor design within an upgraded heavy-duty pump housing, the Dieselsite LPOP rapidly charges the front engine oil reservoir to feed both high-demand aftermarket High Pressure Oil Pumps (HPOPs) and critical engine bearings.

Extended engine cranking times, delayed oil pressure rise on cold mornings, erratic high-pressure oil starvation when running high-displacement hybrid injectors or high-volume HPOPs, low gauge pressure at hot idle, and front cover wear are what this pump eliminates. The HEUI injection system on the 7.3L Powerstroke relies on constant volume from the base engine oil pump to keep the front reservoir filled; if base oil feed lags behind HPOP demand under wide-open throttle, injection control pressure (ICP) collapses. The Dieselsite DS_LPOP73 delivers increased oil volume and faster priming to ensure the HPOP reservoir never runs dry, protecting the turbocharger journal bearings, bottom-end rod and main bearings, and valvetrain. It is a complete bolt-on high-volume LPOP kit including the precision outer housing, matched high-flow internal/external gerotor gears, and mounting hardware; front crankshaft seals and harmonic balancer repair sleeves 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.

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
• High-volume design flows over 8% more oil volume than stock OEM pumps
• Precision-machined gerotor gears provide tighter running clearances and reduced pressure bleed-off
• Eliminates long crank times by providing faster oil priming to the HPOP reservoir
• Prevents high-pressure oil starvation when running upgraded HPOPs and large-displacement injectors
• Stabilizes base engine oil pressure at high operating temperatures and low hot idle
• Direct bolt-on replacement for factory front cover-mounted oil pump
• Includes upgraded pump cover, precision-matched gerotor set, and mounting bolts

Park the truck on a level surface, set the emergency brake, and disconnect both negative battery cables. Release the serpentine belt tensioner with a 1/2-inch drive breaker bar and remove the accessory drive belt. Unbolt the cooling fan shroud and remove the fan clutch assembly using a 7.3L fan clutch wrench kit to gain clear working clearance in front of the crankshaft pulley. Remove the center harmonic balancer bolt using a heavy-duty impact socket, then thread a three-bolt harmonic balancer puller into the damper hub to draw the balancer off the crankshaft snout (do not use a jaw-style puller on the outer ring). Thoroughly clean the lower front cover area of dirt, grease, and road grime. Unbolt the factory oil pump cover bolts from the front engine timing cover and slide the old housing and gerotor gears off the crankshaft keyway. Inspect the aluminum sealing face on the front engine cover for scoring or grooving; lightly stone flat or dress minor imperfections to ensure proper gear side-clearance. Coat the new Dieselsite internal and external gerotor gears generously with clean engine assembly lube or fresh 15W-40 diesel oil to guarantee instant hydraulic pickup upon startup. Slide the inner drive gear over the crankshaft keyway, fit the outer gear into the Dieselsite housing, and install the assembly onto the front cover. Torque the housing retaining bolts in a crisscross pattern to 10–12 ft-lbs (120–144 in-lbs), inspect and replace the front main crankshaft seal if necessary, reinstall the harmonic balancer with an installer tool, torque the center crankshaft bolt to 212 ft-lbs, reinstall the cooling fan and serpentine belt, and crank the engine to verify immediate base oil pressure on the instrument cluster gauge.