Took my 2014 6.4 with 90K in for an oil change and asked them to listen when it's cold as it's been making some noise. Just got a call that both exhaust manifolds are leaking and need to be redone. The dealer acted stunned and said they had never seen it on the 6.4, only the 5.7 but I'm pretty sure I've read about several cases of the 6.4 on here. I have one of the older 6.4s at 5+ years so this could turn into a common thing as more of them age. Lifetime Maxcare covers it otherwise I'd be looking at $2200 so I guess the good news is my warranty just paid for itself. Anyway, just thought I'd make a post here in case others experience the same thing.