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 HD 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 a friend's '04 F-350 dually. Check out what we discovered.
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.
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.
The EGR Cooler and the Domino Effect
The illustration 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.
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.
When Bulletproof Diesel started our project, they warned us about the likelihood of cracked valve seats on the heads of our donor rig's engine. If ever there were a time and place to pull the heads and check for this, it was then.
Our donor truck had just over 40,000 miles on it when we arrived at Bulletproof Diesel. Despite being completely unmodified, many of the valve seats of the cast-iron heads had developed cracks. While these heads offer great flow characteristics, thanks to having four valves per cylinder, the lack of hardened valve seats makes them prone to premature failure. The porous iron material that was used for the OE heads isn't capable of withstanding the high heat and pressure developed during the combustion process. The result is the formation of small cracks where the valve contacts the machined seat surface. Bulletproof had our donor's heads Magnafluxed to check for cracking. Magnafluxing is a process whereby an electromagnetic field is applied to the material, in this case the cast-iron heads. Once the magnetic field is applied, a small amount of colored metallic dust is spread over the magnetized area. When the metallic dust meets the surface, it reveals cracks immediately, thanks to interruptions in the magnetic field. This inspection method allows very small cracks to be visible to the naked eye.
Like most engines manufactured today, the stock 6.0L utilizes head bolts that are designed to twist and stretch to a specific torque value to do their job. This means that as torque is applied to the head of the bolt, the shank or body of the bolt must twist as the bolt stretches to create clamping force. According to Ford, the 6.0L head bolts should be tightened to 85 ft-lb of torque. Head studs do not twist; instead, they use threaded nuts to stretch the stud and create clamping force. Due to the nature of the design, head studs can provide much greater torque values over standard head bolts. Greater torque helps ensure that the head gaskets remain sealed when cylinder pressure and combustion temperatures spike. The published torque spec for a set of ARP head studs for the 6.0L is 210 ft-lb-more than twice that of OE head bolts.
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
How It Worked
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 as part of a towing special in next month's issue. Stay tuned.