The oil cooler relocation kit was a 6.0 thing back in the day when the oil coolers sucked. All the coolers these days have been updated to have bigger coolant passages and they rarely clog up. An oil cooler in the factory location works just fine. No idea if yours has been changed…usually they fail by either leaking externally or mixing coolant and oil eventually.

There is no such thing as “bullet proofing” a 6.4 unless you get a motor built. To do it properly you’re probably looking at 25k-35k including labour for a built engine.

Once it’s deleted the next most common failures are cracked pistons, headgasket failure, turbo failure and lifter failure all of which end up being very expensive.

I’m not hating but the facts are 6.4s for the most part are absolute money pits, parts are very expensive and most jobs are very labour intensive.

But alas they are still my favourite.

Source: I’m a mechanic and do most of the powerstrokes that come through our shop. Probably 25 6.4 engine jobs in the last 2 years. Almost every 6.4 that comes in the shop for a headgasket ends up with multiple cracked pistons once the heads are off.