Well, this is new. White smoke billowing out of exhaust pipes for the first 5-10 minutes after starting the truck. Is this irrefutably a blown head gasket, or might it be something else? 2008, 5.4, 4WD.

 

Dumb question, but are you sure it's smoke & not steam during warm up?

If it is smoke / potential blown head gasket, I would check 2 places for other signs.
1) Oil - does it look milky or smell strange?
2) Coolant - does it have oil floating, also look or smell strange?

If you want to go further with a more invasive investigation, you could pull all the plugs & check for signs of a blown head gasket.
You could also put a scope down the plug hole to see if one (or more) of the cylinders looks too "clean" or actually has coolant in it.
If coolant is getting into the chamber, it will look cleaner than the standard carbon layer you should find on the piston top.

 

Yes, I'm sure it's smoke and not steam. I've lived in Colorado my whole life and I know what cold weather steam looks like. This is an obvious issue.

 

Ok.
You might be surprised at how many don't seem to know the difference.

I would do the "easy" check then & move on to checking the oil & coolant for signs of cross-contamination.
As a side note, have you checked with an OBD2 scanner to see if there are any "irregularities" that might let you know where this is happening in the engine?

 

No, I haven't scanned it yet since I don't have an engine light yet. And to be clear, which protocol are you calling the "easy" check? Thanks.

 

By "easy", I mean doing 2 things to start with:
Pulling the dip stick & checking the stick for the oil condition.
Opening the cap on the coolant tank & seeing if there is any contamination in the coolant.

BTW - you don't have to have a CEL to find info from the scanner. Not all codes set CEL & some can be pending, etc...
As an example, some scanners (the more $$$ ones) would allow you to do a "relative compression" test.
I would think you should see a cylinder with water vapor in it will have higher compression compared to the other cylinders.

If you want more checks or don't see much then you could do these.
"Mildly easy":
Do an oil change to see what comes out & what the filter looks like.

"Moderate easy":
Pop the drain on the coolant & see what comes out.

"Mild invasive":
Pull a plug from a suspected cylinder & get a bore scope down there to see whats going on inside there.

If you still don't see anything then before tearing off a head (or 2) I would pull all the plugs & pressurize the cooling system.
Once you have the system pressurize you WILL find coolant seeping into 1 or more cylinders.
At that point you will know what you are about to get yourself into.

 

Water vapor is a natural byproduct of the internal combustion engine and it processes, and cooler weather cooling pipes cause this vapor to condense into visible white vapor and even water drops from tail pipes. Once the pipes warm up, it fades away from view.

 

Take off oil fill cap with the engine running to see if air blows out of the engine, indicating a possible bad PCV valve. They don't usually go bad with normal oil changes and they are usually hard to get to on Fords. They also cost about $150.
In the past, I've seen V8s with bad valve stem oil seals smoke like that until warmed up.