More than one million 6.0L Ford Power Stroke vehicles are on the road today. Despite an exceptional torque curve, an impressive power-to-weight ratio, and a surprisingly compact package size, the 365ci Navistar International-built V-8 suffered from a series of reliability and warranty issues during its short lifespan. In response, Navistar redesigned, tooled up and built the improved 6.4L version of the Power Stroke for '08-'10 Ford Super Duty trucks. As a result, pre-owned 6.0L Ford pickups are in abundant supply, and are often a few thousand dollars less than a similarly equipped diesel pickup of the same vintage from Dodge or GM. For those of us diesel enthusiasts with mechanical aptitude, the 6.0L Power Stroke is possibly the best late-model pre-owned truck value going today.
Upgrades and troubleshooting strategies for this truck are numerous. One company that specializes in all things Power Stroke is Bulletproof Diesel of Mesa, Arizona. The company's owners, brothers Ken and Gene Neal, have invested a ton of time and money into resolving problems associated with the 6.0L. As the name implies, Bulletproof Diesel products circumvent expensive repairs and costly downtime while providing the reliability that Super Duty owners expect from their trucks. We put their upgrades to the test recently on an '04 F-350 dualie. Check out what we discovered.
This diagram shows how engine oil moves within the 6.0L Power Stroke engine. Notice the a
Diagnosing the Patient
In almost every case, 6.0L engine failures can be attributed to shortcomings in the oil cooling system. In this section, we will cover the how and why of these failures and showcase a proven solution.
1. The 6.0L Power Stroke engine has a unique oil temperature regulation system that relies on engine coolant to raise or lower oil temperature within a given operational range. The system utilizes a compact aluminum heat exchanger that is located in the front of the engine, just under the oil filter assembly. The 6.0L engine block features a void that allows the cooler to mount inside the "V" of the engine. The self-contained stacked-plate heat exchanger is highly effective when the engine is new. However, over time the narrow interior passageways can become restricted by corrosion, debris in the coolant, and casting sand left over from the manufacturing process. This picture shows a cooler that Bulletproof Diesel cut in half with a bandsaw. Despite having roughly 45,000 miles on it, this unit was compromised. Notice the discolored areas in the passageways between the fins; this is the material that creates the restriction. When this happens, coolant flow is significantly impacted. If left unchecked, this lack of coolant flow creates a domino effect that eventually leads to catastrophic engine failure.
2. To solve the coolant restriction issue, many companies offer aftermarket coolant filtration devices that mount between the engine and radiator. While these units do in fact remove contaminants from the cooling system, they do not address the corrosion issues common to aluminum heat exchangers and coolant. However, the approach Bulletproof Diesel took is different. Rather than simply filtering contaminants from the coolant, they redesigned the system so that engine coolant and oil circuits are completely separate from one another. The Bulletproof kit utilizes airflow to regulate oil temperature. Shown here, the system features an aluminum air-to-liquid cooler that mounts just behind the grille, in the front of the vehicle. The secondary benefit of this system is that it eliminates the often-troublesome OE oil filter and cooler assembly and replaces it with a patented oil transfer block, with a remotely mounted spin-on-style oil filter that offers several benefits over the factory setup. We will discuss these a little later.
3. At the heart of Bulletproof Diesel's 6.0L oil system upgrade is a trick billet aluminum transfer block. The unit completely replaces the factory cast-aluminum oil filter housing. In doing so, engine oil is redirected to the front of the vehicle where a large aluminum cooler and filter assembly further improve upon the factory design. This block is manufactured on a CNC mill to specific design tolerances established by the engineers at Bulletproof Diesel. To the best of our knowledge, nobody else offers a unit of this kind. We like the fact that the transfer block utilizes the OE gaskets and hardware to retain the assembly to the engine. Once the cab of the vehicle is free from the chassis, the installation of the transfer block is a simple bolt-on affair.
4. Here, you can see Bulletproof Diesel's ASE certified technician, Justin Aguirre, removing the turbocharger from the top of the engine. This is the first step in the process of disassembly. If the cab of the truck were still attached to the chassis, this procedure alone might take half a day to complete. Instead, Aguirre had our donor truck's engine completely stripped down to a bare block in the same time frame.
The EGR Cooler and the Domino Effect
The illustration to the right details how coolant moves through the 6.0L Power Stroke engine. Notice that after coolant leaves the oil cooler, it flows to the exhaust gas recirculation (EGR) cooler. The EGR cooler uses engine coolant to remove heat from a portion of the spent exhaust gases as they're directed back to the vehicle's intake to help reduce the creation of NOx (nitrogen oxide) emissions. The EGR system is a vital component of the emissions control system. Some companies sell EGR block-off devices that eliminate the functionality of the EGR system altogether, though these kits are for off-road use only and typically cause the "check engine" light to illuminate. The better solution is a Bulletproof EGR cooler with an improved core structure for better flow characteristics.
This is where most failed EGR coolers eventually end up. Bulletproof Diesel purchases the
Inside the EGR Cooler:
Two Common Problems
If you have owned a Ford Super Duty pickup with the 6.0L engine, chances are you have experienced an EGR cooler failure. Ford released several technical service bulletins to its dealer network in an attempt to resolve these problems. However, none of them address the root cause of the problem, and though the dealership may replace faulty EGR coolers under warranty, the issues will continue to persist. Once you've seen the inside of one of these EGR coolers as we have, it's easy to understand their shortcomings.
1. This is an example of a failed EGR cooler that caused a catastrophic engine failure. Notice the cracked coolant passageway (arrow). This unit failed because of a clogged oil cooler and excessive exhaust gas temperatures. This type of failure is typically caused by running an aggressive tuner or chip on a 6.0L with coolant flow issues. You see, the EGR cooler is the next place engine coolant goes after leaving the factory engine oil cooler. When the coolant side of the oil cooler is restricted, the EGR cooler cannot cool hot exhaust gases effectively. The EGR cooler was never designed to handle extreme heat and therefore develops a rupture or crack. When this type of failure occurs, coolant will mix with exhaust gases inside the EGR cooler—not good.
2. This photo shows the other type of EGR failure that Bulletproof Diesel encounters regularly. Exhaust gases deposit gunk on the cooling fins inside the EGR cooler. This causes restriction within the unit. This restriction cuts down on the EGR's effectiveness, allowing higher exhaust gas temperatures to reach the intake manifold. Generally, this type of failure can be traced back to a clogged engine oil cooler. As the coolant side of the oil cooler becomes restricted, less heat is scavenged from the engine oil. This results in higher coolant temperatures and a lower volume of coolant exiting the oil cooler. As the restricted and hot coolant reaches the EGR cooler, the hot exhaust gases "flash-boil" the coolant in the adjacent channels of the EGR cooler. This failure usually results in loss of coolant from the coolant reservoir. This condition typically leads to a rupture failure of inside the EGR cooler, and eventually results in blown head gaskets.
3. The redesigned Bulletproof EGR cooler features a much more robust interior, with six round stainless-steel tubes in place of the factory three oval-shaped tubes. The benefits of this upgrade are staggering. Thanks to improved coolant flow, the EGR cooler can remove heat from exhaust gases effectively. Improved coolant flow cools exhaust gases better, which helps to prevent gunk deposits inside the cooler. The design also prevents the coolant from flash-boiling, thanks to decreased dwell time inside the unit. When coolant and exhaust gases pass through the EGR cooler as intended, heat can be removed from the exhaust gas before it is blended with the air charge. The result is cleaner combustion with fewer emissions.
OE Oil Filter Issues
The Ford 6.0L uses a cartridge-style oil filter element that is located on top of the engine.
To access the element, a black plastic cap is turned counterclockwise. As this cap unscrews, the element inside releases a spring-loaded drain valve that allows oil in the filter housing to drain back to the oil pan. One common problem related to this setup involves people trying to perform oil filter changes themselves. Many Power Stroke owners don't realize the importance of oil filter maintenance. Rather than twisting the filter from the housing as is common in a number of OE applications, the 6.0L unit must be pulled straight upwards. Twisting this element can cause big issues for the lubrication system. The filter element has the felt gasket material that helps seal the bottom of the element to the filter housing. When the element is twisted, felt particles can scuff off and remain in the lubrication system. This debris can clog the nylon oil screen located above the high-pressure oil pump. When this nylon screen clogs, it usually breaks and allows the entire lubrication system to become contaminated. The 6.0L's fuel injection system depends on a clean supply of engine oil to function. Enough contaminated engine oil can easily foul up the injection system, resulting in poor fuel delivery and ultimately poor engine operation. Bulletproof Diesel replaces the weak nylon screen with a robust stainless-steel version manufactured and sold by Ford. This upgrade prevents high-pressure oil system and fuel injection system failures.
1. With the factory front bumper removed, it's easy to see the location where Bulletproof Diesel relocates the engine oil filter. The system uses a much larger oil filter that, by design, cannot introduce contaminants into the lubrication system as the factory setup often does.
2. Here you can see the felt pad at the bottom of the factory oil filter element. This design inevitably introduces particles of felt into the lubrication system. By eliminating this arrangement altogether, Bulletproof Diesel can assure customers that the 6.0L's oil filtration needs are met.
3. Another part that we like about the Bulletproof Diesel oil upgrade is the additional port arrangement included with the system. Thanks to additional pressure and return ports, the system makes it super-easy to add upgrades such as a gauge or auxiliary cooling unit. We took advantage of this opportunity and added a bypass oil filtration device from Amsoil. A bypass oil filter continuously filters a small volume of engine oil whenever the engine is running. Think of it as an automatic oil change every time you drive the vehicle. The bypass filter shown here removes impurities down to 2 microns and leaves your oil the color of honey. We used fully synthetic 5W-30 Amsoil engine oil for this project because it offers superior protection for the various wear surfaces within the 6.0L Power Stroke. We also replaced the engine's antifreeze with the new Super Duty coolant from Be Cool. This coolant comes premixed and ready for use. It is compatible with all types of engine coolant, has a 267-degree boiling point and protects engines for up to 300,000 miles.
4. The Amsoil bypass filtration system includes a billet aluminum oil cap with a built-in return fitting. We like this setup because it allows you to physically inspect the oil after the bypass oil filter does its job. With the engine idling, you can open the cap and see the clean oil as it is returned to the engine.
5. With the new Bulletproof Diesel upgrades completed, the technicians reinstalled the factory front bumper and double-checked the fluid levels. A three-hour test drive ensured that the system was functioning properly across a variety of different driving conditions. We left Mesa confident with Bulletproof's work.
Our Honest Opinion
The improvements Bulletproof Diesel made to our donor F-350 required extensive man-hours to complete. All said and done, our bill totaled $ 7,500 for parts and labor (not including the Be Cool and Amsoil products). But when you stop and consider that this truck is used primarily for hauling expensive construction equipment to and from the jobsite, the expense is easily justifiable. The people at Bulletproof Diesel know their stuff, and with their product solutions installed, this Super Duty's owner has a new restored sense of confidence in his vehicle.
We don't recommend attempting this type of project without a vehicle lift. The process of removing and reinstalling the cab to the chassis requires extensive knowledge of several critical vehicle systems—not something you want to attempt at home with floor jacks. However, the upgrades are straightforward once you have access to all sides of the engine. As with any project of such depth, we expected a few days of driving would shake out anything that may have been overlooked. Much to our surprise, after nearly 5,500 miles of service, the owner of our donor Super Duty reported no major problems associated with the vehicle. The engine oil temperature is no longer tied to the temperature of the radiator coolant, and because of this, the engine runs cooler on long grades and while pulling trailers. Now that we have resolved all the common issues associated with our 6.0L-powered donor rig, we plan to follow up with a selection of power and efficiency upgrades.