Pretty sure I’m in trouble … 2017 F250 6.7 diesel leaking fuel

I’ve got a 2017 F250 with 156k miles, and I’ve put about 10k miles on it since I bought it. Today, while working, I got a low fuel pressure warning. I figured it was just a filter issue, so I scheduled a fuel filter replacement along with my oil change tomorrow.

On the way home, I started smelling diesel in the cab, and almost immediately, the truck lost power. I managed to limp it a few miles back to my apartment, but fuel was pouring out from underneath.

Did I just experience the catastrophic fuel system failure people talk about? What could cause this kind of leak while the truck is running?

It could be as simple as a broken hose or a loose connection. Get a flashlight and take a closer look underneath.

Zen said:
It could be as simple as a broken hose or a loose connection. Get a flashlight and take a closer look underneath.

Something broke or a

Hose fell off. Need to get a

Light and take a look.

That’s actually a haiku and oddly poetic, lol.

@Emerson
That’s awesome. Good bot.

Check the upper plastic fuel filter near the driver’s side firewall. Those filters are known to occasionally crack and leak.

Shane said:
Check the upper plastic fuel filter near the driver’s side firewall. Those filters are known to occasionally crack and leak.

Exactly this. I drive a 2016 6.7, but my coworker has a 2018, and his upper fuel filter has cracked twice now.

Shane said:
Check the upper plastic fuel filter near the driver’s side firewall. Those filters are known to occasionally crack and leak.

That’s exactly what happened. Unfortunately, I broke the return line while changing the filter. I had to rig it temporarily and ordered a better part from SPE Motorsports.

Machines don’t just throw warnings for fun, especially low pressure alerts. Continuing to drive it probably made things worse, but anything can be fixed.

Ashby said:
Machines don’t just throw warnings for fun, especially low pressure alerts. Continuing to drive it probably made things worse, but anything can be fixed.

I figured since it didn’t go into full limp mode or give me a check engine light, it was okay to baby it home. I didn’t push it, just coasted a few miles.

@Milo
Low pressure warnings are always a stop-and-fix kind of thing. But hey, lesson learned, right?

Check two main areas: the connections on the upper fuel filter on top of the valve cover, and the drain knob on the fuel tank. Smelling diesel in the cab points to the upper filter as the likely culprit. Don’t run the engine while checking—just cycle the key to prime the system and look for leaks.

@Vance
Thanks for the advice! When I cycled the key, I noticed a small amount of fuel leaking, so I’ll focus on that area.

Once it’s fixed, you’ll be good for another 156k miles. I’m a big fan of the 6.7. If it were a 6.4, I’d tell you to swap it for a gas engine.

Peyton said:
Once it’s fixed, you’ll be good for another 156k miles. I’m a big fan of the 6.7. If it were a 6.4, I’d tell you to swap it for a gas engine.

I don’t get all the hate for the 6.4. I’ve seen plenty of 6.7s in the shop with less than 100k miles, while my 6.4 is running strong at nearly 300k.

It’s been really cold here today—could this be a gelling issue?

Milo said:
It’s been really cold here today—could this be a gelling issue?

It’s possible. If there was water in the system, it could’ve frozen and caused something to crack.

Turns out it was the fuel filter. Either the dealer lied about replacing it, or I need to be more careful about where I get my fuel.

You might’ve had debris hit the lower fuel filter housing and crack it. Just a guess, though.

If you had fuel pouring out, it’s almost certainly the upper fuel filter. Let us know for sure when you figure it out.

Lennon said:
If you had fuel pouring out, it’s almost certainly the upper fuel filter. Let us know for sure when you figure it out.

You were right—it was the fuel filter! I was worried it was going to be much worse.