Got a minor fuel leak on my 2003 F-350 7.3L TD… any ideas?

Advice Needed
1

Hey all, I’ve got a small fuel leak on my '03 F-350 7.3L Turbo Diesel. It’s on the left side of the truck, just behind the driver’s side front wheel. I checked behind the fuel filter, and it’s completely dry there, so I can’t seem to trace where it’s coming from. The truck still runs fine (though I’m not driving it with the leak). Any thoughts?

2

Check the lines between the pump and the fuel bowl.

3

Those two fuel lines that run behind the power steering pump like to rot out.

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Harley said:
Those two fuel lines that run behind the power steering pump like to rot out.

Yeah, I had a similar issue—there are hard lines in that area, and one of mine failed a while back. Ford stopped making them, but you might find replacements at a junkyard.

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Harley said:
Those two fuel lines that run behind the power steering pump like to rot out.

Thanks for the heads-up, I’ll check it out!

6

I’ve got a small fuel leak in the valley. I replaced the sensor there, which helped for a bit, but it eventually started leaking again from somewhere else. It’s been dripping for over two years, but hey, it keeps the back of the engine clean! I’ll probably deal with it if it gets worse… or the truck catches fire. :joy:

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@Wendell
Funny thing—that’s the only spot without any frame rot! :joy:

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Have you checked the fuel pump on the frame rail? It’s in that exact spot. Loose connections there can cause leaks.

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Kade said:
Have you checked the fuel pump on the frame rail? It’s in that exact spot. Loose connections there can cause leaks.

Checked it, and it’s dry as a whistle.

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I think there are two quick connections in the fuel system between the engine and the front crossmember around that area.

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Behind the driver’s front wheel? That’s where the lift pump is, inside the frame rail. Look around there and be ready to get a pump and line repair kit if needed.

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Leith said:
Behind the driver’s front wheel? That’s where the lift pump is, inside the frame rail. Look around there and be ready to get a pump and line repair kit if needed.

I checked there, but the moisture seems to be above that area, which is why I’m stumped.

13

Fuel lines rubbing under the mounting clamps is a common issue. Try following the supply and return lines to see if that’s where the leak is.

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Update: Found a tiny pinhole in one of the lines going to the pump. Thanks so much for all your suggestions—this should be a pretty easy fix!