My 2018 5.0 has the common cam phaser rattle and knock when idle, no CELs. My local Ford dealership told me its nothing to worry about it even with my truck being out of warranty (77k miles). What are the concequences of not fixing this? Any one have experiences to share with it? Can it wait until I do new timing chains and phasers at 100k miles? Thanks!

 

The problem with putting it off, as I found on our '12 Expy 5.4L, is that the plastic guides can start to come apart if a chain is beating them up because the tensioner also failed.
On my '15 F150 5.0L, changing the 4 solenoids and oil changes at 3-4k has stopped it from stalling at stops, but I can still feel rough idle. It doesn't make the rattle though.
However from what I understand, that rattle could be the phaser itself coming apart, or the chains slapping guides if the tensioner failed.
I wouldn't put that off.

 

Good info, thank. I have read the start up rattle is the chains slapping around. The knock is from the cam phaser not locking out and having additional play, from my research. It goes away when I apply throttle. Was able to easily pinpoint the knock with a stethoscope to the cam phasers on the driver's side.

 

There you go, applying throttle puts the tension on the chains. Our Expy went from 'oh that's not a good noise' to 'holy $&@%' at a gas station in western Kansas on a road trip.
Sorry you're in that camp, hope you get it fixed!

 

When it comes to matters like this, when the dealer says its no big deal.......its a big deal.

Get it fixed.