The 6.0L Power Stroke was introduced halfway through the 2003 model year in Ford's Super Duty trucks. The 6.0L Power Stroke was far superior to its predecessor, the 7.3L, which amongst other reasons, ultimately had to be retired because of its failure to meet stricter emissions regulations of the time period, with even more strict requirements in the future. Unfortunately, the 6.0L Powerstroke proved to be less reliable than the 7.3L and was subject to a number of repeat issues and failures.
Head Gaskets: The 6.0 uses TTY (Torque to Yield) bolts to secure the cylinder heads to the engine block. The 6.0 only uses 4 bolts per cylinder, which is insufficient in most cases. As power levels are increased, cylinder pressures will increase, which will put more strain on the cylinder heads, head gaskets, and the head bolts, (that are already stretched to their MAX) and will eventually lead to failure.
The Fix: ARP or Gator Head Studs, new head gaskets, and mill cylinder heads. Head studs provide greater clamping force than TTY bolts. With the heads milled down, the new head gaskets will have a much better surface to seal against.
High Pressure Oil System: 2003 to early 2004 the 6.0 used a round aluminum pump, which was known to have a high failure rate. In late 2004, the pump was updated, along with the rest of the high-pressure system. While the updated pump had less failures, the rest of the updated high pressure oil system was prone to leaks. The O-rings on the standpipes and dummy plugs would start leaking, which would bleed off injection control pressure causing the truck to run rough, no-starts while hot, or not starting at all. The STC (snap to connect) fitting will also leak, causing a no start condition.
The Fix: A quick air test to the HPO system will reveal the leaking/failed component. Typically, it is good practice to replace the standpipes and dummy plugs on both sides of the engine at the same time.
Turbocharger (VGT): The 6.0L Power Stroke is equipped with a VGT (variable geometry turbocharger). A variable geometry turbo uses teardrop shaped vanes that direct the exhaust gases towards (or away) from the turbine inside the turbo which decreases spool times offering quick throttle response and a wider operating range making the trucks well suited for towing. Unfortunately, the VGT vanes can become clogged with soot and stick in the open position. When this occurs, throttle response is non-existent, and the truck will not get out of its own way. 2003 to 2005 model year engines also suffer from an insufficient oil drain tube. This can result in oil coking in the turbocharger and has been known to cause complete turbo failure in some instances. 2006 and 2007 model year engines received an upgraded oil drain tube to solve this problem, and 2007 model year engines had a revised oil passage to further reduce the chances of turbo failure.
The Fix: There are two options. You can remove the turbo, disassemble it, clean it, and reassemble with a rebuild kit. Option two, you can replace the turbo with a new or remanufactured unit. A new Garrett turbo is without a doubt the best option these days, as a new turbo is affordable, making it the most cost-effective choice.
FICM: The FICM (Fuel Injection Control Module) resides on the driver side valve cover of the 6.0L Power Stroke. The FICM supplies 48 volts to the injector solenoids to control the oil flow into the injector. Engine heat and vibration is known to contribute to premature FICM failures. FICM failures are responsible for a number of rough running, no start, hard start, and stalling conditions.
The Fix: FICM failure can only be fixed by replacement. However, depending on how it failed, a cost-effective solution is to replace the power supply board inside the FICM.
Injectors: HEUI (Hydraulically actuated, Electronically controlled Unit Injector) injectors rely on high pressure oil to pressurize fuel in the injector body. Essentially, the high-pressure oil pump pressurizes engine oil and sends it to the injector, and a piston/plunger in the injector uses the oil pressure to pressurize fuel before it is injected into the engine’s cylinder. The injectors are sensitive to poor fuel quality, and more importantly-oil quality. The 6.0L injectors in particular are prone to stiction. Stiction occurs between two precision ground surfaces, (the spool valve and the end cap), when a thin film of oil is present creating a hydraulic lock between the two surfaces.
The Fix: While there are products out there that will help with stiction issues, the only way to properly fix stiction issues is to replace the injectors. Updated Injectors have a relief cut in the end cap for the spool valve which allows for the oil to properly drain from the injectors.
Oil Cooler: The oil cooler resides in the valley of the engine, and its sole purpose is the keep the oil cool to prevent damage to the engine. The oil cooler has very small passages, and residual sand from the block casting contributes to clogging of the coolant side of the cooler. Poor oil quality can also clog the oil side of the cooler, and occasionally the oil cooler gaskets have been known to fail. An oil cooler failure is suspect if oil is present in the coolant or vice versa.
The Fix: If the oil cooler is clogged, sometimes backflushing can help, but in our experience, the proper fix is to replace the oil cooler, flush and change the coolant, change the oil, and install an aftermarket coolant filter.
While these are only some of many recurring issues with the 6.0, The key to avoiding and fixing these issues with the 6.0L Powerstroke is to understand the cause of these issues. If you understand the cause, you can fix the issue properly and prevent further failures, making the 6.0L a decent engine.