Coolant Pump And Filtration In One From DieselSite

The 7.3L Power Stroke is known as one of, if not the most reliable diesel powerplant ever offered in a Ford. While it’s not the most powerful engine, it really doesn’t suffer from many major problems. One problem it does have is the water pump.

The factory block is manufactured using a sand-casting process which, unfortunately, contaminates the coolant passageways with sand. This sand wreaks havoc on the water pump. This particular 2001 7.3L has gone through five water pumps since purchased in 2002. By filtering the sand and other contaminants out of the coolant, water pump life will be increased greatly. This is not new technology as heavy equipment as well as semi-trucks have been filtering their coolant for decades. For some reason, the light duty diesel pickup manufacturers never offered coolant filters as original equipment.

We’ve worked with DieselSite for some time. They have a multitude of smart upgrades for early Power Strokes and they truly know their stuff. When we saw their latest offering in the form of their new water pump with integrated coolant filter, we knew we just had to check it out.DW

The first step is to drain the coolant. This is done via a petcock on the driver’s side of the radiator. The lower radiator hose was also removed at this time.
Next the degas bottle was removed. The lower hose can be a bit hard to get to so we found it easier to remove the three 8mm bolts securing it and then the bottle could be lifted up, making accessing and removing the hose clamp much easier.


After removing the spare tire tools and the two fan shroud bolts, the fan clutch could be unthreaded from the water pump. Then the fan, clutch and shroud were removed as an assembly.


Removing the upper radiator hose came next. The use of a hose removal tool (basically a 90-degree hook) to loosen the hose prior to removing it makes this job much simpler.


Next, we used a ½-inch drive socket wrench to compress the belt tensioner which allowed us to remove the accessory drive belt.
The factory Ford water pump seen here was almost ready to be pulled.
Next, the heater hose could be removed using a set of slip-joint pliers. Specialty tools are also available to help remove these tension-style clamps.
With the heater hose removed, we then disconnected the temperature sensor electrical plug, removed the upper radiator hose from the thermostat, pulled all nine bolts securing the water pump to the timing cover, and finally removed the pump.
Unbolting the pulley was done using an impact gun on the four bolts. Using anything other than an impact will prove problematic, as the pulley will just spin, stopping the bolts from unthreading. Grabbing the pulley with a set of pliers or a bench-top vise to stop it from spinning will just damage it, so an impact is really the only way to go.
Old vs. new—the DieselSite pump is made from stronger cast iron vs. the OEM cast aluminum pump, and also has a different lower radiator hose mount. Remember, this pump style was originally used on International 7.3Ls that were installed in heavy equipment, so DieselSite’s design utilizes a new high-end silicone lower radiator hose. DieselSite also incorporated other small changes to make installation in a Ford a simple bolt-on affair.
Ford’s thermostat housing is made from stamped steel which corrodes easily and can cause a leak. DieselSite offers a black anodized billet aluminum version that’s much stronger than the factory unit and will last the life of the engine, we’re sure.
The new pump requires a different thermostat be used, which is included in the kit. The new thermostat is also a higher-temperature unit. It opens at 205 degrees versus the Ford part’s 197 degrees. DieselSite’s Bob Riley tells us that the 7.3L simply runs better at this higher temperature. One reason is that diesel combusts better at this higher temp. While it’s not a huge difference, Bob says to think of it this way: “at 211 degrees water is a liquid, at 212 it’s a gas.” A small change can make a big difference.
The old heater supply is relocated with the new design. We threaded this barbed fitting into the pump with a bit of thread sealant.
We removed the water temperature sensor from the old pump and installed it in the new DieselSite pump, in the factory location.
Here’s the best part of this pump: a built-in coolant filter. The valve above the mount is there to stop coolant from leaking everywhere during filter changes (seen here in the off or closed position). DieselSite recommends changing this filter every three months for the first year, and then once a year after that.
The pump’s complete and almost ready to be bolted on.
Before installing the pump we cleaned the mounting surface with a bit of Scotch-Brite and a rag to be sure we had a perfect seal.
DieselSite’s instructions really took the guesswork out of this swap, especially when it came time to bolt up the new pump. Bolt lengths are different and using the wrong length bolt in the wrong hole could cause leaks, or worse, timing cover damage. Replacing the timing cover requires removal of the entire engine from the truck. Directions are there to prevent this from happening.
When finally installing the pump, we grabbed two bolts and only slightly threaded them in—only a couple of complete turns. This made it much easier to start the other seven bolts. Once all nine were started, we torqued them down to 15-20 ft-lb.
Before installing the filter, we applied a small amount of white lithium grease to the gasket to ensure a good seal.
The heater supply was relocated with this pump so DieselSite provides a length of hose and a union fitting to connect the new pump to the existing heater line.
Pump installed. Next, we reattached the radiator hoses, fan and shroud, degas bottle and sensor connector. After filling the radiator with new coolant, we fired up the 7.3L and checked for leaks. All in all we spent about three hours on this install.

Long Term Update

DieselSite’s pump has now been on our Project 600HP 7.3L for over 60000 es with not one problem to date. When we did our first filter change we cut the filter apart to see just how much junk it filtered out of the system. To our amazement it captured almost a half a cup of sand and other contaminants. For a truck that went through 6 pumps in 13 years, we’re pretty happy with this one and expect it to last for years to come.


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