If you’ve got oil pooling in the 7.3 engine valley (under the fuel bowl/HPOP area), the HPOP is always on the suspect list—especially the rear/end plug and the high-pressure discharge fittings. You can check the valley with a mirror or UV dye so you’re fixing the right leak (and not blaming the HPOP for a turbo pedestal mess).

It's an easier leak to fix than many think. Enter the Riffraff Diesel HPOP O-Ring Kit w/ 7 O-Rings (GZ-8-002). It’s a simple reseal kit designed to stop the common external leaks without buying the Ford “three O-ring” kit and calling it a day.

 

 

What’s in the kit (and why it’s better than the Ford 3-ring kit)

This kit includes 7 Viton O-rings plus a packet of Loctite 680 retaining compound. Ford’s factory kit 2C3Z-9G804-AA only includes 3 O-rings, yet typically costs more—so we added the “missing” seals people end up needing anyway.

 

The “extra” O-rings in this kit:

• IPR-to-HPOP O-ring
• HPOP reservoir fill plug O-ring
• Two internal O-rings inside the discharge fittings (99–03 only) (watch the white nylon spacer in the fitting)

 

Why Viton matters here

These seals live in hot oil, constant heat cycles, and high pressure. Viton is widely used for high-temp, oil/chemical-exposed sealing applications because it holds up better than typical rubber compounds.

 

Install reality: not hard, just keep it clean

Remove the end plug and both discharge fittings, remove the reservoir fill plug, clean and dry the ports, install the new O-rings (including the internal discharge-fitting O-rings on 99–03), apply Loctite 680 to only the first three threads of the end plug and discharge fittings, reinstall and torque, let the Loctite cure, then start and check for leaks.

Full Step By Step Instructions Here: https://www.riffraffdiesel.com/content/RESOURCES/8-002.pdf

Helpful torque/cure notes from the instruction sheet:

• Discharge fittings + end plug: 25 lb-ft (34 N·m)
• Minimum Loctite cure time: 2–3 hours before starting
• IPR to HPOP: 35 lb-ft, tin nut 53 lb-in

 

Important note about the “non-serviceable” rear plug

This kit is intended for on-vehicle repair except the “non-serviceable” plug. If that plug is leaking, the pump needs to come out. You’ll want the serviceable long-threaded plug kit—and you’ll want to keep the Loctite clean and allow 24 hours cure for the long-term repair.

 

Pro tip from the field

That lower plug can be hard to see—techs often recomend using a mirror, and that plug/O-ring leak is common enough to be worth checking early.

Disclaimer: The information provided on this blog is for informational purposes only. We share our knowledge and experience, but we are not liable for any damages, injuries, or losses that may occur as a result of using this information. Situations are rarely cut and dry in the automotive world. Your situation will likely be somewhat different than what we describe here. Use your best judgment and always consult a qualified professional for automotive repairs and modifications. Your safety is your responsibility.