The Most Common Problems With Ford's 6.0L Power Stroke Diesel Engine

Diesel engines, for all their rugged usefulness, can be tremendously polluting. They produce more NOx — nitrogen oxides-based emissions – than gasoline-fed cars, as well as more particulates, aka soot. Both of these are bad for lungs. That's why stricter emissions standards get passed, and when they do, diesel manufacturers replace older models with new, cleaner designs.

Ford's 6.0L Power Stroke diesel engine was built to meet standards that its predecessor, the 7.3L, didn't. The 7.3 had some good years and some bad years, but it was also losing ground to the competition in horsepower. So, in 2003, Ford unveiled its second Power Stroke engine. The 6.0 had features like a variable geometry turbo for a wide power band and exhaust gas recirculation to clean up emissions. It cranked out 325 horsepower at 3,300 rpm and handily delivered 570 lb-ft of torque at 2,000 rpm. 

The new Power Stroke went into Ford's F-Series Super Duty pickups (F-250 to F-750) from 2003 to 2007. Some Ford Excursion SUVs and E-Series vans also used the 6.0. Over the years, those owners who followed the maintenance schedules and left the 6.0 engine unmodified generally got reliable service from it. 

However, the National Highway Traffic Safety Administration's (NHTSA) site reveals consumer complaints and manufacturer communications relating to the 6.0 not starting easily, or at all, or running rough when cold. Let's look at some common problems of the Power Stroke 6.0 leading to these complaints.

[Featured image by Bull-Doser via Wikimedia Commons | Cropped and scaled | Public domain]

Head gasket failure is, unfortunately, often associated with this diesel engine. Some of the signs are the 6.0 misfiring, especially at startup, then running hot or overheating. Passersby might see white or blue exhaust smoke. The oil in the engine, when the oil cap is removed, appears frothy. Other fluids like coolants could be discolored or an unanticipated texture. While colored exhaust and rough idle could indicate a few things, all these signs could also point to a blown gasket. This happens more often when the 6.0 is modified to squeeze out more power. But the squeeze is on the head bolts, really, which stretch and fail under higher pressure and expose the gasket to damage as the head lifts. All model years are susceptible to this. 

Two ways to prevent this failure are leaving the engine as stock, or "bulletproofing" it before the head gasket is destroyed. Bulletproofing means changing out the head bolts and a few other parts to shore up the weaker aspects of the engine.

Ford sells a replacement gasket and head bolts for about $278.46, but it's not a repair for the faint of heart because of the disassembly and cleaning required, not to mention draining and replacing contaminated fluids. Repair Pal puts the average cost for a head gasket replacement on a Ford F-350 Super Duty at a repair shop between $3,202 and $3,634, with labor eating up $1,400 to $1,766 of it.

The signs of EGR valve failure can mimic other problems. But collectively -– or to a sharp-eyed mechanic -– they spell E-G-R. Drivers may also notice lower power and acceleration, knocking, and a rougher idle. If they tested emissions, they would detect increased NOx emissions. They might also notice worse fuel efficiency. All because the EGR valve is not opening and closing as it should.

The job of the EGR is to help the engine release fewer nitrogen oxide (NOx) emissions. NOx are created from nitrogen in the air running through an engine. The EGR valve shunts some exhaust gas into the engine's air intake to change the oxygen content of air fed into the combustion chambers. Lower the level of oxygen, and the fuel will burn more slowly and at a lower temperature, to create less NOx and cleaner exhaust. Recirculating exhaust in this way also gives any unburned fuel it contains a second run through the engine.

Typical reasons for EGR valve failure are wear and tear, manufacturing issues, or soot buildup that freezes the valve in one position. This hurts engine performance and potentially increases emissions, a common problem for all years the 6.0 was manufactured. 

The way to prevent this issue is to clean the valve regularly, removing soot buildup before it interferes with the action of the valve. The fix is the same -– clean the valve. But replacement valves are also available, with a price around $129.95 from Dale's Super Store. 

Is there white exhaust coming out of your truck's tailpipe? Is the engine running hot? These may be signs that your EGR cooler is on the way out. It's a common problem in Power Stroke 6.0 engines from the years 2004 to 2007. The EGR cooler fails from not enough coolant, which is supposed to be coming from the oil cooler. When the EGR cooler goes, it can take out the head gasket, too. That white smoke from the tailpipe may be signaling engine coolant seeping into the exhaust system. 

Preventative measures include taking good care of your oil cooler, which helps keep your EGR cooler happy. All years of the Power Stroke 6.0 diesel have oil coolers susceptible to clogging from contaminants because of their shape, so regular oil and filter changes are very important.

The oil cooler isn't easy to get to and can be overlooked in routine maintenance. If it comes time to replace it, some parts stores thoughtfully sell an oil cooler bundled with an EGR cooler and gaskets for addressing two of the 6.0's pain points at once. Dale's Super Store currently has a kit with EGR cooler, oil cooler, and gaskets for $485.95. 

If you're noticing problems with performance or fuel efficiency from your Power Stroke 6.0, including dismal acceleration, stalling, or difficulty starting, there's another problem that could be lurking behind the Check Engine Light. It could be the Fuel Injector Control Module (FICM) dying on you.

This little command module is in charge of how your fuel injectors work (or don't work), which manage how your truck works (or doesn't work). Sometimes FICM circuit boards get cooked by the engine's heat, sometimes they need a software update, and sometimes it's a wiring harness issue and the correct power isn't getting to the unit. 

There's not much to be done preventatively, but when the correct issue is discovered, repairs can range from changing out the wiring harness, changing out the unit, or simply reprogramming the unit. Unfortunately, if the unit needs to be replaced, it's not a cheap part. FordParts.com lists the MSRP at $735 for just the unit, and no related parts like wiring harness.