Some of the 3.6 engines had timing chain issues that were found to be caused by the crankshaft sprocket wearing prematurely. There was a software update for those cars that altered the oil life monitor to call for more frequent oil changes to improve the life of the timing components. The sprocket materials were improved in subsequent years. I have enough faith in the redesign that we own a 2018 GM product with the 3.6 and I expect no engine issues.
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???
One of the reasons that the Ford Crown Vic and Lincoln Town Car was a favorite of fleets everywhere was that the OHC 4.6 would regularly go 300,000+ miles with no mechanical issues.
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You said it . . . cam phasers
Itās not uncommon for them to fail
Itās a very well known problem 
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Iāve heard of problems with everything from the phasers, guides, and tensioner. I was always unsure what the root of the problem actually was.
The first gen ecoboost motors had tsbās out for ācold start rattleā. If I understand correctly, the noise is due to a loose timing chain rubbing somewhere itās not supposed to rub. The repair is to replace the chain, tensioner, phasers, - the whole shebang, basically.
Do you have ecoboost engines in the fleet you service? Curious how they are faring. Iāll have to buy a new(er) truck some day, after all.
Havenāt seen any yet . . . probably just a matter of time 
simpler is better, as far as Iām concerned
bigger displacement over gasoline direct injection and turbo . . . thatās how I would decide
but I donāt call the shots . . .
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If you buy a new half ton, both GM and Ford have direct injection across the board, I think. GM and Ram have cylinder deactivation.
Soā¦there really is no simple anymore.
Letās not even mention the 8 and 10 speed transmissions.
Oh yeah, autostop / start too for all F150ās. Not sure about GM and Ram.
Iāll cross that bridge when I get to it . . .
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I see your bridge in the distance! Look away! 
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