Fuel Tank Leak

[jdross440]

It appears the valve/fitting on top my fuel tank is leaking and running down into the recess forward of it or the tank is leaking at the recess. It fills and runs over. I just saw it dripping off the tank this week sitting in my driveway. I used a rag today and cleaned out the recess and dried it out. I drove it about 3 miles and let it sit a couple hours. I checked it and it was about 1"deep in fuel. Had anyone else had this problem? The valve/fitting has a barbed fitting but no hose on it. I am attaching pictures.

 

[Wayne M.]

Yep. I’m aware of that fitting, but my tank hasn’t given a lick of trouble since day one.

 

[DavidC]

Is that the roll over valve ?

 

[Crunch]

It appears the valve/fitting on top my fuel tank is leaking and running down into the recess forward of it or the tank is leaking at the recess. It fills and runs over. I just saw it dripping off the tank this week sitting in my driveway. I used a rag today and cleaned out the recess and dried it out. I drove it about 3 miles and let it sit a couple hours. I checked it and it was about 1"deep in fuel. Had anyone else had this problem? The valve/fitting has a barbed fitting but no hose on it. I am attaching pictures.

I've had a similar problem a couple of times over the years. I believe the barbed fitting to which you are referring is the auxiliary fitting. For me the problem was that the lock nut that holds the fuel tank module on was loosening. I would notice it when I was fueling up and saw fuel dripping on the ground under the tank, especially when topping it off. If you have a strap wrench (or the kind that uses a bicycle chain) that is large enough you should be able to use it to tighten the lock nut. According to the Dodge Repair Manual, the proper tool used to tighten the lock nut is "Special Tool 6856". The problem is that it is designed to be used when the fuel tank is removed from the truck. I don't have a strap wrench that is large enough to fit around the lock nut and still have enough slack to get a good grip on the lock nut, so the first time I just tightened it by hand. It was tough to get under there and get a good grip on the lock nut, but it moved enough to last a while. The second time it was leaking I got a piece of rebar about 2' in length and secured it the best I could in the teeth on the outside of the lock nut and lightly tapped it with a small sledge hammer. That was about a year and a half ago, and it hasn't leaked since then. Just don't beat on it too hard. You could break off the teeth or worse, damage the lock nut. If you try this, take note of the tooth location relative to a fixed spot when you position the rebar (a small diameter galvanized water pipe should also work) so you can see if, and how much the lock nut moves when you tap on it.

 

[EDankievitch]

I had an issue with that fitting on my 05. I think Dodge had a rubber cap on the fitting. There was a 2nd one on the back end of my tank. I used some small 1/4" fuel line and connected the two together. I didn't want water or getting into the tank. And I didn't know if it had to vent. connecting the two together I felt was the best option.

 

[xcc_rider]

Iirc it's a rollover/vent valve. You have to determine if it's leaking out the barb fitting or the gasket to fix it properly.

There were/are issues with the vent in the tank recess sucking in water and dirt that accumulated in the recess.
The mod was to connect both vents together with hose and a T fitting and then run another hose up over the frame cross member leaving the open end pointed downwards so as not to suck anything in. I did this and added a cheap inline fuel filter for added protection.

There was a Mopar kit that does the same thing for the 2007.5 and 2008 trucks.
Starting with the 2009's they came pre installed.

Haven't had any issues in 12 years.

 

[B.G. Smith]

If it only leaks when completely full it,s probably the nut that holds the fuel pump/sending unit in the tank. My 99 did that when it was new and I just tightened the nut by using a wooden dowel and a small hammer tighten. If it is leaking when tank is not full then I would suspect the fuel pressure or return line at the tank. The fitting is the rollover valve and must be left open or you will end up pulling a vacuum on the tank as fuel is used. Don't think your tank has the small vents at either end.

 

[jdross440]

Mine is dry on top around the sending unit. This is the first time it has leaked in 200k miles. I will get some 5/16 hose and run up somewhere above the top of tall end of tank and see if this solves the problem.

 

[SKrugerud]

Had the same problem with the front barbed fitting (vent). Best I can figure is that dirt got in there and fouled the seal. After dropping the tank and coming up with no fix other than replacing the tank I added 18” of fuel line to each barb, installed a lawn mower fuel filter to keep any more dirt from going in and then ran both lines up (left plenty of slack) like a standpipe and attached them to the bottom of the cab with stainless clamps. They still can vent properly and most likely leak out the barbed end, but the fuel never leaves the hose.