HAREBRAINED IDEA OR SMART BUY?

Make That Dirt-Cheap 6.0L a Reliable Daily Driver

They’re cheap for a reason. They’re nothing but problems. They’re junk.

We’ve heard it all before. These words of warning are common for any prospective buyer of a used 6.0L Power Stroke. After all, the Navistar-built V8 offered in ’03-07 Ford Super Duty’s, was plagued with a slew of design flaws from the very beginning. Some items on the laundry list include fuel injection problems, cooling and emissions systems error, and the lingering concern for potential gasket failure. However, there’s something about paying $10-12k for a low-mile, four-wheel-drive, crew cab diesel that continues to lure people in.

DW-1811-FDTECH-02 — Even with all the 6.0L’s shortcomings, most of the failures can be averted by performing proper maintenance. This includes observing Ford’s “severe duty” oil change interval of 5,000 miles, running a synthetic and lower viscosity oil for better cold weather performance, and ensuring you change both fuel filters every 10,000 miles. After comparing multiple brands, we highly recommend you stick with Motorcraft filters (PN FD-4616). Additionally, if you leave the EGR system untouched, make sure you test your coolant every 15,000 to 20,000 miles. By using coolant to drop exhaust gas temperatures from 1,400 to 350 degrees, the 6.0L’s EGR system is very tough on coolant.

DW-1811-FDTECH-03 — First thing’s first—plan on monitoring engine coolant and engine oil temperature to see if an oil cooler repair is needed. Engine oil temperature should stay within 15 degrees of coolant temp when the engine is up to operating temp. Anything beyond the 15-degree range and it’s likely time for a new oil cooler or equivalent. Oil cooler failure is one of the most common problems on a 6.0L. The stacked-plate heat exchanger is notorious for plugging up on the coolant side, thereby superheating the engine oil and sometimes even taking out the EGR cooler in the process. Such a bypass would result in increased performance but at the expense of emissions testing failure and engine deposit buildup.

DW-1811-FDTECH-04 — The EGR cooler faces failure on two fronts. First, when the aforementioned oil cooler plugs up and stops the flow of coolant through the EGR cooler the extreme heat can cause it to crack or burst along the welds. Second, due to the EGR cooler routing spent exhaust gases back to the intake manifold, the constant exposure to soot leads to accumulation. This buildup of soot, carbon and grime eventually hampers internal flow, leading to excessive heat, which can (once again) cause the EGR cooler to rupture. When the EGR cooler cracks, coolant is allowed into the engine’s exhaust or intake and the problem is often misdiagnosed as a blown head gasket.

DW-1811-FDTECH-05 — Never repeatedly replace a 6.0L’s EGR cooler without digging deeper. More than 90 percent of all EGR cooler failures are caused by a clogged oil cooler blocking coolant flow to it. This is precisely why most reputable shops install a new oil cooler any time the EGR cooler is replaced.

DW-1811-FDTECH-06 — In an effort to give exhaust gases more travel time before passing through the EGR valve on their way into the intake manifold, Ford added a longer EGR cooler to the 6.0L starting on ’04.5 models (left). However, its square-tube design ended up being more prone to soot accumulation (and ultimately failure) than the circular unit used on ’03 to early ’04 engines. Per the folks at Bullet Proof Diesel—a company that offers emissions-compliant, direct-fit replacement and ultra-reliable EGR coolers for the 6.0L—the square, late-style EGR cooler was added to engines built on or after September 22, 2003.

DW-1811-FDTECH-07 — Another emissions system component that’s prone to plugging up, sticking and failing is the EGR valve. Once through the EGR cooler, the EGR valve meters the amount of cooled exhaust gases introduced into the intake tract. Like the EGR cooler, the valve is constantly exposed to a mixture of soot and blowby, which culminates in an impenetrable buildup of grime that hinders the component’s operation. If you plan to leave your 6.0L’s EGR system intact, make it part of your maintenance regimen to remove and clean your EGR valve on a regular basis. They can begin to stick and even seize in as little as 20,000 miles of use.

To be sure, the problems associated with the 6.0L Power Stroke have been extensively documented. However, there are some situations where buying a cheap diesel-powered ’03-07 Ford can pay off. The key is whether or not you’ve got the mechanical experience to make (and keep) one reliable. If you adhere to a strict maintenance schedule, know how to diagnose a problem when it arises, and you’re no stranger to turning a wrench, you can all but eliminate the bulk of the costs involved in keeping a 6.0L on the road.

Subscribe Our Weekly Newsletter

Don’t believe us? Keep reading for a list of the 6.0L’s most common failure points, along with how they can be fixed or upgraded. You might just find that the 6.0L isn’t half as bad as you were led to believe.