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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3,000 miles if using the proper weight full synthetic is just a waste of resources, 5k is the low 7.5k is what Iād go for on the max, many of these have you going over 10k, my wifeās Explorer has 40% life at 7,500 but i change it at 7,500 since that usually around 7 ot 8 months so i donāt even change it twice a year since we put on at most 11k miles a year, my 2011 CTS Iāve owned for about 3 months and have under 1,000 miles on it
Auto start stop is on all new cars as California has made it mandatory on cars and SUV, as they arenāt for gas mileage but emission reasons, but first thing I do when I get in my 2021 Explorer is turn that off, only some newer GM have the cylinder deactivation system, but it can be easily defeated by a OBDII device, which Iād definitely get if I had this
The two people to whom youāre responding havenāt been active in this forum for several years. Scrappy has been gone for ~2 years, and Caddyman seems to have disappeared about 7 years ago. This is an old thread.
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That post is just ignorant of OHC systems, and it seems heās implying that a timing belt is more durable than a timing chain, which is completely wrong, as you mentioned if itās well maintained a timing chain can last well over 300k, a timing belt no matter the manufacture is going to need to be changed at 100k or 10 years no matter how well you maintain your engine
The biggest issue with the 3.6 timing chains falling is two well 3 things, 1 the 2012 and earlier had a designed flaw with the PCV valve causing to much oil consumption which can be fixed with a valve cover gasket, 2 is the oil level sensor was poor designed and wouldnāt go off till you were 2 to 3 quarts down, though even with this flaw the owner bares some of the responsibility as they really should check there oil level at every fill up ot at least every other fill up, 3 was the system did over estimate oil life, and the low oil is what would cause the timing chain and more importantly the tensioner to be properly lubricated
The biggest problems with the early ecoboost was in order to keep the turbo lag all but unnoticeable was to cast the exhaust manifolds with the block, but in doing so they ended up with extremely close quarters between the cooing ports which didnāt give enough surface to form a proper seal and coolant would begin to leak into the cylinders and into the oil causing catastrophic results, they have addressed that, but the more recent ecoboost issue was caused by engine intake valves that fractured and fell into the combustion chamber. It was revealed that the material the valve supplier used was not up to specification, but they claim this issue has been addressed
On the I3 and I4 Ecboosts. the the manifold in built into the block. However on the V6 Ecoboosts, the manifolds are not built into the block.
You are correctā¦āthere is no replacement for displacementā ā440 or bustā.
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