The Key Differences Between Early and Late Model ’03-’07 Power Strokes

If you own a 6.0L Power Stroke, you have an engine that is at least 14 years old. And if you haven’t yet had to venture under the hood, you soon will. Contrary to what many outsiders believe, catastrophic engine failures are few and far between with the 6.0L. However, intermittent component failures are inevitable and can sideline you and your truck if you aren’t prepared, or aware of this engine’s common quirks. It’s equally important to mention that as these trucks age and become even more affordable to purchase on the used market, more and more owners perform their own repairs rather than take them to a dealership or an independent shop. It’s just the nature of the beast.

In the following pages, we’ll spell out the primary differences between early and late engines, as well as the changes that were implemented beginning in ’05. Some of the distinctions are obvious (the 10-blade ’03 VGT vs. the quieter 13-blade turbo on ’04-‘07s), while others (such as different cams, pistons, glow plugs, and water pumps) are more obscure. By knowing exactly which version of the 6.0L Power Stroke you’re dealing with, it’s our hope that the information contained here will remove all guesswork from your required repairs.

Running ’03 & ’04 Model Year Changes

Most folks are aware that there were a boatload of subtle updates made between the ’03 and later versions of the 6.0L Power Stroke, but many don’t know that the pistons were different. Almost exclusively driven by emissions standards, ’04 model engines—beginning with serial number 6155637 in Indianapolis and serial number 0094580 at the Huntsville, Alabama plant—featured a crown with a smoother radius (right). This was done to increase the efficiency of the combustion event (namely to clean up particulate matter emissions). The piston’s skirt and ring lands were unchanged, as was its overall diameter. The beginning production date for’04 engines equipped with the updated pistons was September 29, 2003.
As a result of the piston changes that were integrated into the ’04 engines, shorter glow plugs were used. The glow plugs are exactly 1.2mm shorter than the versions employed in ’03 engines, so in order to avoid potentially catastrophic engine carnage through piston-to-glow plug contact make sure you don’t install longer, ’03 glow plugs in an ’04 or newer 6.0L. As for the glow plug module, beginning in ’04 its bracket was altered in order to accept the new positioning of the relocated ICP sensor (more on the ICP sensor in a bit).
The design of the aluminum intake manifold remained similar for ’04, but the rear cross plate, which was originally intended to equalize pressure on both sides of the manifold, was eliminated. The MAP port and the intake air temperature sensor remained located in the intake manifold, however.
When the exhaust gas recirculation (EGR) cooler was changed for the ’04 model year 6.0L Power Stroke, Ford advertised it as being longer rather than highlighting the fact that it was no longer round in shape. While the updated EGR cooler was in fact longer, its design was square and in time would prove more problematic—in terms of carbon buildup—than the ’03 engine’s EGR cooler had been. The intent of lengthening the EGR cooler was to give exhaust gases a longer run (i.e. an increased interval for cooling) before being introduced back into the intake stream.
One major change between ’03 and ’04 model engines was the addition of the EGR throttle plate, or EGRTP. Located in the intake manifold, it was designed to reduce manifold pressure so that exhaust gases could flow more freely into the intake manifold. The EGRTP sensor is a potentiometer that provides an electric feedback signal to the powertrain control module (PCM).
In addition to the turbine wheel change, the way the turbocharger was mounted in the 6.0L’s lifter valley was also altered for 2004. A new turbo mounting bracket incorporated bolt spacers into the bracket itself, and allowed the required clamp load to be achieved for the turbo’s mounting bolts. Current part numbers for the ’03 turbocharger and the ’04-’05 unit are 725390-5006 and 743250-5024, respectively.
Although a lot of folks in the 6.0L Power Stroke realm enjoy the whistle of the ’03 engine’s variable geometry turbo, Ford didn’t feel the same. To quiet the Garrett GT3782VA down, a 13-blade turbine wheel was added for the ’04 model year. The ’03 model year turbocharger’s 10-blade design provided the pronounced whistle the 6.0L became immediately known for. Despite the change in blade count, the diameter of both the turbine wheel’s exducer and inducer remained the same.
Midway through the ’03 model year, the 6.0L was treated to an oil supply line update for the turbocharger. Instead of utilizing a quick-connect fitting at the oil cooler, the new design featured a hold-down collar secured with a bolt. Ford made the update in order to eliminate the possibility of an oil leak, as well as increase long-term reliability of the hard line.
Reducing engine noise while simultaneously increasing volume, the wavy style high-pressure oil rails were introduced in ’04. While it’s unclear whether the acoustic wave attenuation (or AWA) features actually helped to decrease the 6.0L’s pronounced engine noise, the wavy rails did provide a 15 cubic inch volume increase, which reduced the chances of ICP falling off during injection events.
To accommodate the new, wavy style high-pressure oil rails, revised high-pressure stand-pipes were required (right). Each two-piece stand-pipe is sealed to the high-pressure oil rail and the high-pressure oil branch tubes via O-rings. Note: if disassembled, always replace the stand-pipe O-rings or the stand-pipes themselves. Neglecting to do this can lead to a high-pressure oil leak developing down the road.
To meet the tighter emissions standards set to come into effect on January 1, 2004, a different profile camshaft was introduced on all ’04 model year engines. The cam’s lobe lift, lobe separation angle, and duration were all changed in order to improve the engine’s combustion events. We’ll note that while camshafts can be interchanged between ’03 and later model year engines, for emissions purposes it isn’t recommended.
Most of us recognize the difference between an early high-pressure oil pump and one off of an ’05-’07 engine, but for 2004 models Ford reported that an updated pump made the cut. Ford and International literature from late 2003 states that a revised high-pressure oil pump—utilized in conjunction with the new, wavy style high-pressure oil rails—had the capability of producing increased oil pressure over the ‘03 version.
For ’04 model year engines, the ICP sensor was relocated to the right bank high-pressure rail and received a new gasket. Previously, it was mounted in the high-pressure oil pump cover at the rear of the engine. The ICP sensor itself can be replaced without removing the valve cover. Why was this such an important change? The ICP sensor is a key component in diagnosing high-pressure oil issues on the 6.0L Power Stroke, so it stands to reason that having better access to it makes any troubleshooting process one step easier.
Already known for its injector troubles by late 2003, a notable change geared toward longevity was added to ’04 model 6.0L engines. The plunger in each injector was treated to a Diamond Like Carbon (DLC) coating to guard against poor fuel quality and reduce scuffing within the barrel.
Due to the injection pressure regulator’s (IPR) location being so close to the turbo, a heat shield was added for the ’04 model year. The heat shield is secured around the IPR through the use of a metal snap button. It can be unbuttoned and slid off the IPR with ease.
For improved coolant flow through the engine, all ’04-later 6.0L’s received a water pump with a 100mm diameter impeller vs. the 90mm impeller employed on ’03 water pumps. In addition to improved flow, it provided improved heat rejection. It’s worth mentioning that both the ’03 and ’04 water pumps have the same bolt pattern, but different sealing areas. An early water pump should never be installed in an updated front cover.
On early production 2003 model year 6.0L Power Strokes (top), the engine wiring harness was made up of two small harnesses which were combined. These smaller harnesses were strung between the oil filter housing in the valley and the secondary fuel filter housing. However, beginning on late production ’03 engines the two harnesses were separated in order to increase serviceability and longevity. From late ’03 6.0L’s onward, the injector harness was routed between the oil filter housing and the turbo’s compressor housing (spanning from the FICM to the injectors).
Before the high-pressure oil pump cover was altered for the ’04 model year with the relocation of the ICP sensor, a subtle change was made midway through the ’03 model year 6.0L’s production. The original HPOP cover utilized a sleeve to provide a sealing surface for the O-ring on the high-pressure oil discharge tube. Halfway through the original production year’s run, the sleeve in the cover was eliminated and the sealing surface for the high-pressure discharge tube was totally machined for the O-ring seal.
In an attempt to improve injector serviceability, Ford revised the orientation of the injector retaining clip. Before the change in ’04, the retaining clips were positioned on the side of the injector connector in the 9 o’clock position. To make its removal easier on all cylinders, every clip’s orientation was changed to the 12 o’clock position.
Another change implemented in the middle of the ’03 model year was at the injector clevis. A redesigned clevis provided improved lateral support for the plunger within the injector, and was said to dramatically reduce scuffing. Between the DLC coating on the plungers and the clevis update, Ford and International made a valiant effort to offer a better injector package in late ’03 and ’04-later engines.
Coinciding with the new, wavy style high-pressure oil rails, the crankcase breather had to be externally mounted on the driver side valve cover for ’04. To accommodate the new crankcase breather, the inlet hose for the turbocharger’s compressor inlet was updated. Note that the compressor inlet hose’s bracket is also purposed as a retaining bracket for the FICM.

’04.5/’05 Model Year Changes

Not unlike the early 6.0L Power Stroke, a multitude of changes took place midway through ’04 and especially for ’05 engines. In addition to picking up another 10 lb-ft of torque in ’05 (570 lb-ft at 2,000 rpm), the ’05 model year 6.0L received emissions, turbocharger and injection system updates that were geared toward improved reliability.
Not unlike the early 6.0L Power Stroke, a multitude of changes took place midway through ’04 and especially for ’05 engines. In addition to picking up another 10 lb-ft of torque in ’05 (570 lb-ft at 2,000 rpm), the ’05 model year 6.0L received emissions, turbocharger and injection system updates that were geared toward improved reliability.
Unfortunately, the infamous snap-to-connect (STC) fitting made its way onto the outlet side of the HPOP in ’04.5, and it would become one of the key failure points going forward, often revealing itself in hot re-start situations. The ultimate fix for this leaky connection point in such a vital area is to install Ford’s update kit, which reverts back to a threaded fitting similar to what was employed on ’03 and early ’04 engines. The part number for Ford’s update kit is: 4C3Z-9B246-F and you can pick one up for $55 to $65.
As for the Garrett GT3782VA turbo itself, the journal bearings were increased in size in the form of being made 1mm longer. This is said to have made the turbo’s rotating assembly more robust, although journal bearing and thrust bearing failure was never a big issue with any model year 6.0L engine. Unfortunately, the unison ring—what mechanically moves the turbine vanes—is the common failure point in all GT3782VA turbochargers.
The high-pressure oil pump was changed in ’05 in an attempt to improve the HPOP’s reliability and low-rpm engine performance. The new HPOP remained located at the rear of the lifter valley and driven by the camshaft, but the high-pressure discharge tube and branch tubes had to be redesigned. The ’05-later style HPOP isn’t interchangeable with ’03 or ’04 engines.
Accommodating the new HPOP for ’05 was a redesigned, cast-aluminum pump cover. The IPR valve was now mounted in the top of the HPOP rather than through the HPOP cover, and the cover itself was sealed via an O-ring. The oil draining from the turbocharger continued to route through the HPOP cover.
In addition to being repositioned directly in the cast-in provision at the top of the HPOP (vs. the HPOP cover), the IPR valve was treated to a 150-micron, perforated plate edge filter for ’05. This improved on the previous 200-micron filter for finer oil filtration. The button-secured IPR heat shield introduced for ’04 continued to be utilized throughout the rest of the 6.0L’s production.
Nearly as quickly as it appeared, the EGR throttle plate was gone. By ’05, engineers at Ford and International found that the EGRTP had no real efficiency advantage in EGR operation, and thereby eliminated it completely. However, an exhaust gas scoop engineered into the passenger side up-pipe was implemented to increase exhaust flow to the EGR cooler, which in turn is said to have improved the performance of the EGR valve without the need for the EGRTP.
To facilitate equal distribution of post-EGR cooler exhaust gases into the intake manifold, the ’05 model year and later intake manifold incorporated two internal divider plates. A cast-in divider plate exists on both sides of the EGR valve at the front of the intake manifold.
To keep exhaust gases from leaking out the EGR valve’s vent holes (a common problem on ’03 and ’04 engines), the 6.0L received an updated EGR valve with an improved shaft seal for ’05. Part of the solution was the EGR valve’s use of a return spring with increased tension. The updated EGR valve can be identified by the part number 4043H located on the top of it. It cannot be interchanged with ’03-’04 engines.
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