I bought a `99 F150 supercab 4x4 XLT with the 5.4 last week with only 34, 600 miles on it and it started smoking yesterday.
Yep, I have the dreaded passenger-side head gasket leak. Took it to the dealer today and was informed that they will tear it down tomorrow and see if I need a new engine or just a new gasket.
I was told that if the block or head had "dimples" on the gasket surface, then I would get a new head or engine, depending on which was affected. Dealer was nice enough, despite me insisting rather forcefully that a new gasket will not fix it and that I wanted a new engine.
I guess I'll find out if this new dealer is competent.

 

Consider yourself lucky for being under warranty. Sounds like you'll soon have a new engine. Most of the time the head gasket is just a band-aid. Some 5.4's have a bad casting causing the gasket to leak.

 

Do you know which 5.4 have the bad casting?
Terry

 

Good question, Terry, is it a specific production date range? Is it a specific serial number range? Just scattered throughout the entire production of 5.4's or ????

 

From the information I've read on this board and others, it seems it is scattered between 99-01. Hope my L doesn't come down with this problem later on.

 

The problems began back in the early 99 model, when they went through and re-tooled the engine lines, and that is when the head gasket problems arose. I for one had one that started to leak at 18,000 miles, and they fixed it with a new gasket, well that lasted 8,000 miles, and then they fixed that problem by replacing the engine with a new engine directly from the line. I have had that engine in there since I had 32,000 miles on the truck, and haven't had any more problems with the leaking head gasket.
I have read a few in the newer models but nothing like the early 99 models. There can't be a specific plant that the engines came from either, because mine was made in the Windsor plant, and a buddy of mine that had an early 99 had a engine that was done in the cleveland plant, and his leaked as well, and they would just replace his head gasket, and not the entire engine....They fixed it, and it leaked agian, and he insisted on a new engine, but they wouldn't do it, even with my paper work in hand stating about the problems with the 5.4l.
Hopefully this helps out, but just from what I have gathered, it is done with in the new models.
David