My dad’s 2012 F-450 won’t let us put any fuel in the tank. We tried disconnecting the breather tube but no luck. For context, we had to run it down to empty (dashboard says 0 miles) because of the hurricane here in Western North Carolina, and we couldn’t find diesel fuel for a while. Now that we found some, it won’t go in. Anyone dealt with this?
That sounds rough. Since you disconnected the vent, I doubt it’s a clogged vent tube. Follow the filler neck and make sure it’s sloping down properly. Sometimes it can get pinched or bent, causing the fuel to back up. Check if it’s doing that anywhere.
We weren’t using a funnel at first, but we tried that as a last resort.
How fast are you pouring? Sometimes these trucks are picky with diesel flow. You might need to set the pump to a slower flow or pour really slowly to avoid it kicking back.
I was pouring at a medium pace. It takes about 3 minutes for the fuel to go through the filler neck and into the tank, but it fills up before reaching the breather.
I’ll check it out tomorrow. Thanks for the suggestion.
No problem. Good luck! It’s so frustrating when fuel won’t go in.
I’ve never heard of this happening before. That’s wild!
Yeah, me neither! I’ve tried everything I can think of. 
Go slower and pull the funnel out a little so air can flow around it. If you’re using a gas can, pour the diesel in sideways slowly to avoid spills.
Like I mentioned, we tried the funnel as a last resort.
You could try going underneath and pulling the filler neck off. There should be one clamp and maybe a few small screws near the fuel door. If you’re confident you can put it back on right, check for obstructions. I’ve done this before, and I’m 6’3”, 200 lbs, so you should be able to fit under there!
I’ll give that a shot tomorrow. Thanks!
No problem! Also, use hand tools instead of electric ones when working around fuel, even though diesel isn’t as flammable as gasoline, it’s still combustible, so better safe than sorry.
Yeah, I’ll stick to hand tools or maybe air tools. I’m not that crazy to use electric tools around fuel!
Check if one of the fuel filters has a red bleeder valve. If it does, loosen it and try filling the tank again. When you see fuel coming out without bubbles, you should be good. If not, you may need to bleed the injectors one by one.
Is the truck sitting at an odd angle? Could be a gravity issue.
I wish it was that simple, but with no fuel, we can’t exactly move the truck! Or maybe I can just use magic and get it running without fuel. 
Haha, sorry, I was just joking about the picture being sideways. Couldn’t resist! Did you manage to sort it out yet? We had some Rams at work that wouldn’t take fuel, and it took forever to fill them up.
No worries! I thought you meant the truck was in a ditch or something. But yeah, it’s frustrating as hell.