2008 Ford F250 6.4 PS purchased at 115k miles completely stock. Had it fully deleted with a mild tow tune shortly after. Been an awesome trouble free truck until it blew the head gaskets after an over boost incident pulling a trailer in Witchita at 260k miles. Had the head gaskets done almost a year ago by a local shop who was very familiar and had experience with the 6.0s and was told to be good at what he does. I use this truck to pull trailers long distances and practically gave the guy an empty check to fix everything that looks at him funny "I need this to be reliable". Well I've got a little over 10k miles on truck now and it's puking under a load.. not much though. Heater core isn't air locking, and I made a 8 hour round trip and it never got hot. The guy told me he checked and made sure the heads and block were flat and looked for any wear and tear, but never sent the heads off anywhere. He ARP studded the heads replaced the gaskets, replaced rocker arms, the oil cooler, glow plugs, fixed several oil leaks. He said only way to investigate is to start stripping it down again.. Excuse my ignorance, but could I possibly get away with re tourqing the heads? Or is this most Likely a warped head issue? How would you guys proceed from here if you were in my shoes?

 

Retorquing head studs after you've blown a composite gasket is like wearing a condom after she's pregnant. On an MLS gasket retorquing might work, but not a composite gasket.

There is some conflicting information out there on the need to retorque head studs. ARP even says its not necessary. But,,, the retorques aren't for the studs, its for the gaskets. The head gasket will relax and crush a little further after a few heat cycles. I've gotten as much as 1/4 turn on head studs to get back to the originally installed torque after running a newly rebuilt engine with a head gasket.

So unless the guy who put new head gaskets on used aftermarket MLS gaskets (which are available for the 6.4L) ,then retorquing likely won't help. Good luck with your quest for making a 6.4L reliable, at 260K miles, you've already gotten more miles than most out of one. If you end up replacing head gaskets again, spend the extra cash and have the pistons changed out for some de-lipped pistons while you're that far in, the stock pistons tend to crack.
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Your issue is that the heads didn't get sent off to the machine shop. Period.

He followed the Ford procedure which is to use a straight edge and feeler garage across the middle of the heads. If the feeler gauge doesn't slide under the straight edge, you're "good" to the put the head back on after cleaning the gasket material off it and the deck.

This is never the way to do things. I myself was a victim of this practice on my '05 Excursion. It ran great when I picked it up from the shop, but as I started to use the truck, things began to happen that pointed to leaking heads. In addition to the fact that my heads weren't machined, nothing was torqued properly.

An engine rebuild later with machined heads, a decked block, and PROPERLY torqued heads, my engine is solid.

Bottom line: you'll have to have your heads redone. This time I'd either take the heads to the machine shop yourself or buy some heads from Promaxx, UCF, of KDD.

 

Sounds more like you had a torque issue than a machine issue. You can machine something all you want but if it's not bolted properly you'll never get it right.

 

True, that was a big chunk of the problem. The other half was the un machined heads.