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Home > DieselSite > DieselSite HPOP Reservoir Filter Adapter
Dieselsite HPOP Reservoir Filter Adapter
Fits: 94-03 Ford Powerstroke 7.3L
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Dieselsite HPOP Reservoir Filter Adapter

Fits: 1994-2003 Ford Powerstroke 7.3L

This is a multi purpose design. In addition to the filtration benefits it can be used during the installation of a dual pump setup to eliminate drilling holes in your factory reservoir, or used to supply and return oil for twin turbo set-ups. The hole marked "pressure relief return" in the picture below, dumps oil back to the oil pan down the front cover. This is a perfect place to return oil from a twin turbo configuration.


  • Increase reservoir capacity
  • Adds filter screen to 1996 (Engine Serial Number 201681) Through Mid 1999 (Engine Serial Number 1039779) 7.3L Engines
  • Factory fuel filter (1999-2003) housing still bolts in place, but minor relocation of the lines are needed
  • Comes complete will all items shown - new gaskets and all hardware for installation

The Powerstroke uses high pressure oil to activate the injectors. At start-up, the high pressure pump (HPOP) draws oil from the reservoir to start the engine, and the low pressure pump is refilling the reservoir with unfiltered oil until there is engine oil lube pressure. This allows a small amount of dirty oil from the oil pan to reach the HPOP and the injectors every time the truck is started. Small fine debris will pass fairly easily, but larger debris can cause pump or injector damage. In mid year 1999 (Engine Serial Number 1039779), Ford integrated a filter screen into the front cover gasket to catch any large debris before entering the HPOP. This new "gasket" with integrated filter CANNOT be retrofitted into an older engine as the front engine cover was machined differently to accommodate it. If you do use this gasket accidentally, you will crack the front cover causing a very expensive repair bill.

SPECIAL NOTE: If you go to your Ford dealer to buy a reservoir gasket for your 1999 model year truck, they will give you the new gasket with filter screen. Someone messed up in the application guide. To get the right one for this model year, you must ask for a 1997 gasket. Our adapter comes with all the gaskets and hardware you'll need.

Dieselsite developed this adapter to allow the use of the new style filter gasket in the older engines. All gaskets, bolts, and port plugs are included.

CAVITATION: In testing for the PULSE HPOP and building a dual PULSE pump version, Dieselsite came across something that needed to be addressed. Most dual pumps on the market utilize a 3/8" feed line to the rear pump. Using a stock pump, this is simply not large enough. The rear pump actually pumps at 60% of rated flow. That means your "200%" dual pump is actually pumping 160% of that of stock and the rear pump is slowing tearing itself apart. The noise level from this is deafening when not drowned out by the actual engine noise. I have had some say they can hear a squeal from the pumps but were told it was "normal". Dual stock pumps need a minimum of a 1/2" or #8 line. Our Dual PULSE needed a 3/4" or #12 line!!!! They drilled and tapped a #8 o-ring thread into the adapter for this purpose. Yes, you are reading this correctly. If you install this adapter, and run the larger feed line, your pumps will put out more oil! They will pump what they were supposed to pump. Besides, cavitation will kill a pump of any kind.

Interested in testing this issue on your truck? There is a small #6 O-ring plug on the passenger side of the pump. Run a pressure gauge from this port to somewhere that you can read it while the engine is running. You MUST have at least 3-4psi oil pressure. If you do not have oil pressure here, the rear pump is starving for oil. HPOP's do not suck oil. They must be fed oil under pressure. The factory oil pressure gauge reads "normal" if you have at least 6psi in the reservoir. This guarantees that you have enough oil to feed the HPOP. However, pressure in the reservoir DOES NOT mean you have pressure in the inlet of the back pump. There are tremendous losses in volume and pressure due to friction of the side walls of the feed line to the rear pump.


  • Nice addition to dual pump designs- 2nd HPOP is filtered as well
  • Ports for 2nd IPR return, 2nd HPOP supply, and 2nd relief valve return
  • Bolts into any 1996(Engine Serial Number201681) -2003 7.3L engine
  • Design eliminates cavitation to the rear HPOP in dual pump applications
  • 1994-1995 model
HPOP Reservoir Filter Adapter HPOP Reservoir Filter Adapter
Bottom gasket installed in front cover New adapter stacked over bottom gasket/front cover and screened gasket installed on top of new adapter
HPOP Reservoir Filter Adapter HPOP Reservoir Filter Adapter
Side view looking from firewall with fuel bowl deleted Side view with the fuel bowl reinstalled if you haven't deleted it
Product Description Price Order
HPOP Reservoir Filter Adapter
1994-1995 Ford 7.3L
Part #
HPOP Reservoir Filter Adapter
1996-2003 Ford 7.3L
Part #
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