2005 Ford F350 6.0L Power Stroke Diesel

Danger, Will Robinson!

As this story was being produced, we ran into some information that 6.0L owners might want to heed. We've been hearing reports of head-gasket failures on 6.0Ls that are being worked hard. The "chickens" in that "chick-'n'-egg" scenario appear to be the head bolts, which fail by stretching and allow the head gasket to leak or blow. The same thing is happening to modified 6.0L Power Strokes that are being run hard.

Some will say the change from six head bolts on the old 7.3L Power Strokes to four bolts per cylinder on the 6.0L is the major problem. According to some of the experts we consulted, that's sorta true and sorta not. Yes, there are only four bolts on the 6.0L, but they are very much beefier than the 7.3L's. The gasket is much better on the 6.0, and it was improved for '05. The main problem is that the bolts stretch under high combustion pressures and allow some gas to escape. At first, that happens only under high-pressure conditions, but eventually the gasket degrades and begins to leak all the time. The answers to this problem are studs that do not stretch. There are some high-performance bolts on the market now from Diesel Performance Specialties (DPS) and Automotive Racing Products (ARP), with BD Performance and ATS likely offering kits by the time you read this.

The big question for 6.0L owners is, at what point should studs be factored in with other mods? We spoke to Ken Englesman, the Ford expert at DPS. They have been dealing with these problems from the outset and have had a chromoly stud kit since 2004. Englesman's answer was that any mods producing more than 100 to 130 hp over stock should have a stud kit installed. Definitely mods that include injectables like propane, nitrous, or water should have the stud kits because these all drastically increase cylinder pressure.

Removing the old bolts and installing the stud kit is not a piece of cake. You can pull the bolts and install the studs singly, but the rear bolts are difficult and usually require you to unbolt and lift the cab 5 inches or so for clearance. Englesman's advice is to pull the engine to do the job, pull the heads, and install the improved Ford gaskets at the same time.