Head gasket repair is big business in the 6.0L Power Stroke segment. Whether the Super Duty its powering is straddled with GCWR-crushing loads everyday or has been modified via a programmer, winding up with a blown head gasket is pretty much a foregone conclusion. The dilemma for 6.0L owners is that the tight packaging of the engine within the ’03-’07 Fords isn’t exactly ideal for technicians to work on. This makes the job of replacing the head gaskets a laborious endeavor to say the least. For ultimate working space, the process of pulling the cab quickly became the preferred method of performing a head gasket job on a 6.0L, and to this day 9 out of 10 techs do things this way. But we’ve got news for you: You don’t have to pull the cab to work on this engine. And no, it doesn’t take any longer to perform the job with the cab in place.
The folks at Flynn’s Shop believe a lot of time is wasted while carrying out all the odds and ends associated with separating the cab from the frame on the ’03-’07 trucks. Between evacuating the A/C system (and recharging it later), deciding what goes up with the cab versus what stays on the ground, and fighting corroded cab mounts and rusted cab mount bolts, they’d rather just dig in under the hood. And no, they don’t pull the engine.
Discovering coolant residue on top of the degas bottle is a dead giveaway that a 6.0L Power Stroke has blown a head gasket. Once compression is allowed to sneak past the gasket, the coolant system becomes pressurized, and the weakest link in the chain is the purging of the 16 psi-rated degas bottle cap. Chad Flynn of Flynn’s Shop got started by draining the coolant system and detaching the degas bottle. He then removed the front grille. Why does Flynn pull the grille? Because he knows that the two-day job calls for a lot of leaning over the front of the Super Duty, and this rules out the potential for scratching it.
We recently stopped by Flynn’s facility in Alexander, Illinois, to watch the two-day operation unfold on a ’04 F-250. Throughout the teardown, prep, and reinstallation processes, we were privy to the tips and tricks they have picked up on over the years. If the techniques, parts, and workmanship illustrated in this article are put to use on your 6.0L, you can rest assured it will never blow another head gasket.
After removing the serpentine belt, alternator, fan shroud, FICM, radiator hoses, and even tearing down the evaporator core housing, Flynn pulled the air intake and intercooler piping off of the engine. Notice here that Flynn removes the cold side intercooler pipe and intake elbow as one assembly. This is done for two reasons: it speeds up the teardown process and it doesn’t disrupt the tight seal the intercooler boot has. Blown intercooler boots are common with the 6.0L (when under load and elevated boost), so you don’t want to break this seal if you don’t have to.
Next up, Flynn turns his attention to removing the oil and fuel filter assemblies as one unit. Once the fittings are broken loose on the hard fuel lines, Flynn secures zip ties around the lines in order to prevent the fittings from sliding down onto the valve covers or the heads. Flynn also places the oil filter spout in a plastic bag for safe keeping until its reinstalled later on.
With the turbocharger and engine wiring harness out of the way, Flynn moves on to the intake manifold. Prior to its removal, he marks the location of the studs versus the bolts used to mount it to the heads. Knowing which fasteners go where in the intake manifold makes things much easier when everything goes back together.
Any time you’re going this deep into a 6.0L Power Stroke, it behooves you to replace the oil cooler, as it is an even bigger problem on the ’03-’07 Super Dutys than head gasket or EGR issues. Add to that the fact that the average oil cooler only lasts 50,000 to 75,000 miles and you start to see why Flynn replaces it as standard operating procedure during any head gasket job.
The injection pressure regulator (IPR) can easily be removed after the turbo is out of the way, and it should always be pulled before the driver-side head comes off the block. While not as vital as going with a new oil cooler, starting with a fresh IPR never hurts (or a new injection control pressure sensor, for that matter). This valve ensures that the correct amount of high-pressure oil makes it to the injectors, and they retail for between $140 and $200, depending on where you buy one.
Once under the valve covers, Flynn makes quick work of extracting the oil rails, and then uses a 12-point, 3/4-inch socket to free the injector plug-ins from the rocker boxes. Then it’s time to loosen the injector hold-downs and pull all eight injectors.
To keep everything in the valvetrain in perfect sync, all 16 pushrods are arranged (in the upside down cardboard box shown) in the same position they were on the engine. The same was done for the rocker arms and valve bridges. You never want to let an unrelated engine repair disrupt valvetrain components that were operating in perfect harmony.
Next, Flynn began breaking the factory head bolts loose (there are 10 per side), along with the five M8 bolts found in the top of each head. Before prying the heads apart from the block, Flynn made sure that several drain pans were positioned under the engine in order to catch any additional coolant.
Prior to hoisting the cast-iron heads out of the engine bay via cherry picker, Flynn zip-tied four of the bottom five bolts in place on the driver-side head, along with the rearmost bottom bolt on the passenger-side head. This is done because these head bolts can’t be removed due to clearance issues, and you don’t want them to drop down into their respective bore and potentially reengage any threads while you’re trying to lift the head(s). Flynn finds that zip ties work much better than the rubber band trick, which is promoted in the Ford service manual. Also notice the exhaust manifolds are still attached. According to Flynn, there is no need to remove them unless the heads don’t check out OK at the machine shop, and there is no need to disrupt a good seal (only to battle rusted, corroding manifold bolts) unless you have to.
With the heads removed and on their way to the machine shop (for resurfacing and magnafluxing), Flynn was able to pinpoint where the head gasket had failed. Here you can see that the area of the gasket below cylinder number 5 (passenger-side head) was the culprit in allowing cylinder pressure to escape. The remaining coolant was suctioned out of the cylinders via a vacuum.
Using a grinder and Scotch-Brite pad, Flynn began making headway on cleaning up the deck surface of the block. According to him, the primary emphasis is on removing the old head gasket material more than worrying about how flat the block is. On the subject of flatness, Ford specifies that any difference greater than 0.002-inches across any 5.9-inch area on the block renders the crankcase unusable. After Flynn inspected the deck surface with a straight edge and a feeler gauge, our block checked out just fine.
While the 6.0L block typically retains its factory trueness, the same can’t always be said for the cylinder heads. They’re notorious for warping and cracking—and once the cracks protrude into the valve seats its game over (you’re buying $3,000 worth of heads). This is why it’s so important to have your heads resurfaced and magnafluxed by a reputable machine shop. The heads’ maximum allowable difference in flatness can be no more than 0.004-inches across the total surface area. Like the block, our heads checked out OK.
An important tidbit for anyone performing a head gasket job on an early 6.0L engine: if you need new cylinder heads, Ford only casts the later version, which utilizes alignment dowels that are approximately 20mm in diameter (right). However, Ford offers stepped dowels for earlier engines, which came with 18mm dowels (left). The stepped dowels allow an older block to be fitted with the later-style heads.
Due to potential quality concerns with aftermarket head gaskets, Flynn only recommends running Ford replacement units. The multi-layer steel (MLS) OEM gaskets are proven to hold up just fine once head studs are added to the mix. After all, the 6.0L’s blown head gasket scenarios aren’t the fault of the head gaskets, anyway—it’s the factory head bolts that fail.
A combination of the engine’s design only incorporating four head fasteners per cylinder (most diesels employ six) and those fasteners being torque-to-yield head bolts is to blame for most of the 6.0L’s head gasket issues. Under extreme operating conditions, the head bolts stretch beyond their elastic limit and the head(s) lifts as a result. Here you can see two factory head bolts on the left and two ARP head studs (PN 250-4202) shown on the right. Unlike bolts, head studs thread completely into the block and provide superior head-to-block clamping force. ARP’s success rate can best be measured by the simple fact that once 6.0L engines are fitted with a set of its studs, they rarely ever pop a head gasket again, even at higher horsepower levels. It’s no wonder why this is the best-selling fastener in ARP’s arsenal.
Before Flynn placed the resurfaced heads back on the block, he taped off the intake ports and zip-tied four out of the bottom five head studs in place (along with the rearmost top stud) in the passenger-side head. This is done because the studs can’t be installed once the head is on the block. The studs are zip-tied in a way that keeps them slightly less than flush with the bottom of the head. This is a crucial step because you never want to set a head on the block more than once, as it risks damaging the head gasket.
Clearance near the firewall is even tighter for the rearmost fasteners on the driver-side head. Once again employing zip ties, Flynn anchored the rearmost studs in place before lowering the head onto its respective alignment dowel. After the heads were successfully positioned on the block, two M8 head bolts were installed (a little more than hand tight) for added insurance while Flynn began dropping the rest of the ARP head studs into place. Once the studs were threaded (hand-tight) into the block, their corresponding washers and nuts were installed. In order to get a socket on the rearmost bottom stud’s nut, Flynn had to massage the insulation blanket on the firewall in order to clear the ratchet. He told us that on occasion, loosening the motor mounts and lifting up on the engine is enough to gain adequate clearance to tighten this fastener.
In this photo, you can see that only the bottom head studs have nuts on them. This is because the pushrods, valve bridges, rocker arms, and rocker arm dowels have to be reinstalled before the top head stud nuts. Flynn alternates from head to head when gradually tightening the rocker arm bolts. This is done to ensure the lifter collapses before the bolts receive their final torque spec of 23 lb-ft.
The last item of business as far as the 6.0L head gasket fix is concerned is torquing the ARP head studs in the proper sequence. Working from the center out, Flynn torqued the studs in four separate intervals. The first called for 50 lb-ft, the second 100 lb-ft, 155 lb-ft for the third go-round, and 210 lb-ft on the final interval.