This is actually on my 2013 Flex Ecoboost, but engines are similar. On a cold start it rattles briefly. I got the timing chain parts, water pump, oil pump etc. for a full rebuild, however, now that I have the cover off, the chains no loose. Has a little slack, but thats normal.

Talk to me about the phasers. The main difference between the F150 and Flex/SHO/Explorer Ecoboosts is the latter have only one phaser per side, Intake only where the F150 has one on intake and exhaust.

Is what I hear the phasers on cold start? I just don't want to drop another $350 if I don't need to. Is it as common on the single phaser engine as it is on the F150?

 

The phasers have a pin to hold them in the home position during startup before oil pressure reaches them. The hole the pin sits in wears out, the phasers are free to rotate back and forth at startup, so they rattle.


Not sure if the FWD phasers have the same failure mode.