Ask any 7.3L Power Stroke owner how long the engine is expected to last and the answer will be something along the lines of half a million miles, 10 more years, or forever. And while the latter might be true for many of the components bolted to the 7.3L, age and exposure to the elements tends to take its toll on the venerable V8’s oil pan. It’s common for a rusted pan to eventually develop a small leak—but it’s even more common to find oil seeping out of the factory dipstick adapter, which we’ll cover in this article.

What Happens

Over time, the dipstick adapter’s internal O-ring swells, sometimes even severing, allowing engine oil to slip past it. The result is an engine with an oil pan and starter that are perpetually coated in oil, and oil stains on the ground everywhere you park the truck. Tightening the adapter nut only distorts the inside portion of the adapter further, and home repairs made with RTV sealant or JB Weld are anything but a sound solution. To add insult to injury, replacing the factory dipstick adapter calls for removal of the oil pan, which means the engine must be pulled. The situation puts budget-minded 7.3L owners in quite a predicament.

The Fix

Developed as a long-term solution for a growing problem, the folks at Strictly Diesel designed a dipstick adapter repair kit for ’94.5-03 7.3L-powered pickups, vans, and Excursions. The kit eliminates the failure-prone factory dipstick adapter altogether, replacing it with a billet aluminum adapter that utilizes a double O-ring seal on the outside of the oil pan. The best part? It can be installed with the oil pan still on the engine and the engine still in the truck. To find out exactly how Strictly Diesel’s dipstick adapter repair kit works, we sat in on an install at Flynn’s Shop in Alexander, Illinois, where a 22-year-old F-350 was being graced with one.

Before he sent the truck airborne via two-post lift, Chad Flynn of Flynn’s Shop first pulled the oil dipstick and set it aside. He then removed the dipstick retaining bolt that secures the upper portion of the dipstick tube to the engine (shown). On Super Duty trucks the dipstick tube is secured via a retaining nut, and removing the cold-side intercooler pipe provides more than adequate access to it.
Knowing the starter would have to be removed, Flynn disconnected the negative and positive terminals from both batteries (to avoid the possibility of a short). After that, the truck was sent skyward and the three 17mm bolts that secure the starter were removed.
Grabbing hold of the dipstick tube, Flynn dislodged it from the dipstick adapter in the pan. The dipstick tube was then positioned a few inches forward (toward the front of the truck), where it stayed for the remainder of the install.
The adapter nut was broken loose but not yet removed. Per Strictly Diesel’s instructions, the nut was left loose enough to unthread by hand but left in place for the time being.
Before pressing on, Flynn stuffed a piece of paper towel into the factory dipstick adapter port to keep anything from entering the oil pan and cleaned the adapter and its surrounding area with brake cleaner. That was followed by a round of compressed air to dry the brake cleaner and blow any remaining debris off the pan.
While the factory dipstick adapter will remain in the oil pan (more on that in a minute), the original O-ring must be removed. Before he fully unthreaded the adapter nut (which has to be done in order to pull the O-ring), Flynn attached a pair of vice grips to the dipstick tube port on the adapter.
If the factory O-ring falls into the pan, it’s at risk of being sucked into the oil pump pickup. Therefore, after unthreading the adapter nut, Flynn carefully removed the O-ring by using a pair of needle nose pliers to slide it over the top of the aforementioned vice grips being used to hold the adapter stationary
Because it’s impossible to remove the factory dipstick adapter without pulling the oil pan, the original adapter is abandoned inside the pan. Gravity simply takes the adapter to the bottom of the pan, where it can remain indefinitely with no negative side effects (i.e., the material it’s made from won’t break down, won’t hinder flow to the oil pickup, and it’s too large to be sucked into the pickup).
After positioning it as far back in the oil pan as possible, Flynn released the vice grips and let the adapter drop. After hearing an initial clunk on the pan’s side, we listened for the adapter to settle to the bottom. We’ll note that draining the engine oil prior to releasing the adapter makes hearing it hit bottom a little easier. At this point in the install you want to make absolutely certain the adapter has in fact fallen to the lowest point.
Prior to installing the Strictly Diesel adapter, the outside surface of the oil pan must be prepped. As the new sealing surface for the O-ring seal(s), you want the steel to be as smooth as possible. In this case a fair amount of surface rust existed, so Flynn made use of a die grinder fitted with a Scotch-Brite pad to clean things up.
If you’re performing this job on an ’01-03 7.3L Power Stroke, with the dipstick adapter removed you can peer into the oil pan and see if you’ve got bolts or studs securing your rod caps. If you find bolts it means you’ve got powdered metal rods (i.e., PMRs), while the presence of studs means you’ve got the stronger forged steel rods in your engine.
The billet aluminum exterior of Strictly Diesel’s patented oil dipstick adapter is machined from American-sourced T6061 aluminum and features a machined steel brace on the back side (made from 1018 cold-rolled bar stock). It secures to the pan via stainless steel screws with copper sealing washers and comes with a new Ford O-ring for the factory dipstick tube.
The internal brace/backing plate sits inside the oil pan and is pulled tight against the wall of the pan via two stainless steel screws. One of the screws’ ends is welded and can’t be removed (lower screw as shown), which makes it impossible for the brace to fall off inside the oil pan during installation.
For optimum sealing, the Strictly Diesel adapter makes use of a double O-ring seal on the outside of the oil pan (vs. one internal seal used on the factory adapter). When the aforementioned screws in the backing plate are tightened up, the O-rings are compressed against the exterior wall of the oil pan, which not only gives them a longer lifespan but makes them easier to replace should they ever need to be serviced.
Before Flynn installed the new adapter, the welded mounting screw was backed out as far as possible and the second screw (and its copper washer) was removed completely. This allows the exterior portion of the adapter to be rotated into the correct position.
Holding the exterior portion of the adapter, Flynn set the internal side into the oil pan with the backing plate angled toward the rear of the truck. Flynn also made sure to line up the adapter’s dipstick tube port with the reference mark he’d made before removing the factory adapter nut and dropping the old adapter into the pan.
With the adapter engaged with the tab in the oil pan and oriented correctly, a dab of Loctite was applied to the threads of the mounting screw that had previously been removed. Being that there are no nuts to engage, thread locker ensures the screw will never back out of the adapter.
The removable screw was reinstalled in its hole in the adapter but not tightened. Note the circumference of the adapter sitting flush with the surface of the oil pan. This can only be achieved if the adapter is correctly oriented.
Flynn used a 3/16-inch Allen wrench to rotate the welded, non-removable screw until the backing plate made contact with the removable screw. At that point Flynn backed the removable screw out enough for the backing plate to be rotated slightly further using the Allen wrench, at which time the removable screw could be threaded into the backing plate.
Alternating between the two screws, Flynn cinched both down evenly until it was time to torque them. The screws were then tightened to the 100 in.-lb torque spec Strictly Diesel recommends, and for all intents and purposes the installation was complete.
To avoid a potential oil leak where the dipstick tube sits in the adapter, Flynn set about replacing the factory O-ring. Conveniently, Strictly Diesel supplies a fresh OEM O-ring with the dipstick adapter repair kit.
The included OEM dipstick tube O-ring makes use of an interior ridge and a V-shape on its exterior for an optimum seal. Once Flynn installed the new O-ring, the dipstick tube was pressed into the Strictly Diesel adapter, the starter and dipstick tube retaining bolt (up on the engine) were reinstalled, and all battery terminals were reconnected.
All told, installation took Flynn less than 30 minutes from start to finish. From labor, time, and financial standpoints, Strictly Diesel’s dipstick adapter repair kit beats the heck out of the alternative (pulling the engine to pull the oil pan). And while the adapter’s O-rings could easily be replaced, we can’t see them ever being a problem. After all, the average 7.3L will likely need a new oil pan long before this adapter requires attention.
With one oil leak fixed, it pays to be proactive in avoiding another. Since there was a fair amount of rust present around the adapter hole in the pan, Flynn applied a thick coat of flat black paint over the dipstick adapter and pan to fend off any further corrosion.

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