My buddy has a 5.4 SD with 36K on it and he was going through a quart of oil every 350 miles. He takes everything to the dealer for service so maintenance should not be an issue. The dealer had the truck for 20 days and replaced a few seals and gaskets (he's not sure exactly what, maybe valve seals and more) and they told him they were honestly not sure if the problem was fixed. He traded the truck on Friday because he refuses to deal with the problems.

I was concerned about my own 5.4 having a similar problem down the road. His driving pattern is to keep it below 2500rpm at all times and he NEVER goes above 68mph. Has anyone else had a similar problem? The talk around the range is that this is common with the 5.4’s. I checked all the past pages and haven’t seen anything about this. I saw posts on the head gaskets but if it was a head gasket, they probably would have pinpointed that fairly easily. Just throwing it out there to see what you all have heard.

 

my 5.4 uses 1 quart of oil every 3000 miles...and that is AFTER i had the intake and headgaskets replaced and the heads machined...about 86k miles now...i use castrol syntec 5w30 oil

 

I've got a 4.6 that burned old from day 1. 5-30......10/40.... now I'm running 20/50 and it still goes through oil fast. A quart every couple of thousand miles. 120,000 miles on it and nothing wrong. Just have to watch the oil.


Not going over 2500 rpm or 68 mph is foolish, maybe the rings never seated properly. Drive it like it's a rental car!

 

I had this same problem with my Excursion last year. I had a post last March maybe about it. I was fighting with ford because they told me that 1qt per 500mi was normal. After 3 trips back to the dealer and several call to Ford it finally got fixed. Now I use less then 1qt in 3000mi. The Dealer never did say what they found but had the X for days and even put dye in the motor to help find the problem. All this happened around 30k. Now at 50k with no problems. I get 17 mpg on the highway and love it.

 

Sounds like your buddy has a bad PCV valve. It seems like a fairly common problem on 5.4's. Try a search, this has been posted several times. Good news is that it is an easy fix if it is the PCV.