5.4 are really becomming the replacement 6l. Ive had over 10 now with low oil pressure. Ended up change out the long blocks on all of them. doing one as week speak, Ive seen everything from blown tensioners, bad oil pumps, crank journals undersied and all of the cams are scored. lowest pressure ive seen was 14psi at hot idle. Anytime now that i have one with low oil pressure i just pull it and put it in a stand. never had to re assemble one yet and put it back in because of the cost of the repair to the short block. ok yeah seen thrust bearings fail as well. mostly on 07 and a half to 2010. The milage as been anywheres from 40 000kms to 110 000kms. all used ford filters and have regular oil changes. heck one was our service loaner lol.
