Fuel tank vent hose WARNING DANGER ??

[Wasilla Rod]

When filling the fuel tank in my 2004 - 3500, after the initial automatic shut off I could creep in another say 2 gallons before it was FULL. I could hear air hissing out some where above the tank but could not pinpoint it. Took the truck in to where I work and used the 15 ton overhead hoist to lift off the bed. (Too easy!) Found that there are 2 small free hanging 5/16" vent hoses -- one at each end of the tank and the large 5/8" vent that ties intothe tank near the filler hose and the upper end at the filler neck. The small hose at the front of the tank was gone and the back one was only slid over the first barb of the plastic barb -- about to come off. (FACTORY!!) The front "barb" is down in a depression in the tank and there was a slurry of mud, water, diesel and what ever else drifted into there. This had been flowing in and out of the tank with the hose missing. The plastic tank barb was almost plugged. I cleaned up the whole mess and rodded out the barbs with a shop vac sucking on them. Replaced the small hoses being very sure they were pushed all the way on and zip tied over a hump before dropping down beside the tank.

When fuelling your tank --the initial vent is through the 5/8 hose till the automatic shuts off then the remaining creep fill is vented through the small hoses. The front hose is at about the same level as the 5/8 and the back vent comes off a raised bubble section at the back of the tank. There will be fuel comming out the small front hose when you still have about a 2 gallon airspace in the back hump.

This is a pretty poor set up for tank vent. You may want to look above your tank and at least make sure you still have both small hoses hooked up or you will be getting a slurry of junk back washing into your tank!

 

[Prairie Dog]

There was lots of talk on this subject soon after the third gens came out. Mine seemed to be a real odd-ball in that the barb in the depression was molded over (It was as if you had to cut the end off if it was to be used. ) while most others were left open like yours and folks found mud in their tanks. Some had injector problems that Dodge wouldn't cover. I put a length of hose on the other barb and it works well. I don't worry about getting the last 2 gallons in but it will fill with the OTR high volume pumps running at full speed so the single vent is good enough for me. There's nothing like filling your tank in less than 40 seconds!

 

[steved]

Known issue on the early 3rd gens... I think the TSB affected the 05s and older, that's the reason you don't hear much about the issue anymore.

Newer trucks should have the "fix" which is two short pieces of hose.

 

[Blakers]

Many folks put hoses on the two ports and Y'd them together and put a lawn mower fuel filter in the end.

 

[rbattelle]

Here's the thread where Fireman revealed the problem.



-Ryan

 

[NavyDood]

Never did a thing with mine. 157,000 miles later all is well.

 

[Kry226]

Never did a thing with mine. 157,000 miles later all is well.

Me too. 113,000 miles.

 

[Wasilla Rod]

Need to check anyway!

You may not have had "problems" but if your front hose is not on the barb you can be wholesailing crud into your tank and filter because the barb is in a dish and any road splash / dust that gets up there has pretty easy access right into the tank. If you sit right in front of the rear tire with your head between the quarter panel and bed with a flash light you can get a look at the offending area to see if your hose is still there. An extendo mirror might be a good tool also. After seeing the pool of crud that resided in the dish and how dirty the inside of the barb was I am kicking my self for putting off the inspection for so long. LAZY IDIOT!

 

[TimothyLong]

I just recently started having a similar problem with my '03. Like Wasilla Rod, I could get 2+ gallons in after the shutoff from a fuel nozzle. Last week I was filling up and as I was topping off, I heard something leaking. Looked under the truck and diesel was being pushed out from somewhere. Then just this past Friday, when I filled up it did it again after only getting about an extra gallon in the tank. I haven't had the opportunity to get under there and check it out. Mother Nature hasn't been very cooperative lately.

 

[rscurtis]

My signature truck never had these fittings on it. I installed Spooled Up's vent kit when he offered it a number of years ago. Made a big difference in being able to actually fill the tank.

 

[NavyDood]

I have the spooled up kit. Love it for fill times. The two small nipples on top I have never done a thing with. That is what I was referring too.

 

[Blakers]

Well, after putting it off for several years since reading about this problem, today I finally fixed it. Took some old sap tubing that I had lying around and pushed it over the barbed fittings, ran it into a T and up between my cab and box, ending with a small engine fuel filter to act like a breather. Hopefully no damage was done. There were no hoses whatsoever on the barbed fittings on the fore and aft of my tank.

Blake

 

[steved]

They do have a check valve in them, I popped mine by leaving my transfer pump on. It reset after leaving it "suck" a vacuum on the tank.

 

[Blakers]

Which way is the check valve aimed?

They do have a check valve in them, I popped mine by leaving my transfer pump on. It reset after leaving it "suck" a vacuum on the tank.

 

[steved]

They allow air into the tank, but not out.

 

[JMarketos]

As I understood it, crud can get sucked in through those little vents as the truck consumes fuel and air is drawn in there to equalize the pressure (vacuum) in the tank. Worse if the hoses are gone and the barbs are sitting in crud, but I heard it can also happen if the hoses are on, just at a slower rate. Agree with the comment above- this seems like a really poor design- leaving the possibility for unfiltered air to enter the fuel tank. (If I may digress for a moment... If I were an engineer, given that those are supposed to be one way check valves, I'd be concerned that crud could get into the check valve and prevent it from "checking" as intended)

Anyway, I solved this same way as some of the others above, and / but for a different reason... I read on here a few years ago about taking forever to top off a tank due to foaming of the fuel, and there was an aftermarket kit that relocated the fuel tank vent to a different location on the tank, which eliminated the problem. Installing the kit involved dropping the tank. Meanwhile I had read about the small vents crud, so while I had the tank out, I capped both small vents. My fuel fill setup now consists of:
[1] Fills through the main large neck per stock.
[2] Filler neck vent goes to relocated 5/8 fitting at highest point in tank. (not sure if it's the actual "spooled up" kit, but it's from a place I learned about on this forum. )
[3] Original 5/8 vent: Instead of putting a pipe plug in this hose (per the vent relocation instructions), I did something a little different: (because I had capped the two small vents... ) I bought from Summit racing a fuel check valve, like they use in race cars. I adapted it to the 5/8 line and placed the new check valve in a vertical portion of the line (so it operates as intended). I ran this line up the inside well of the bed, near (and just above) the fuel filler door. Above the check valve, I installed an old style automotive fuel filter. (the clear body type, about the size of a couple golf balls). Not using it as a fuel filter, just using its filter element as basically an air filter- a cheaply replaceable barrier between the outside atmosphere. I then put a piece of 3/8 hose on the output (air-side) of that, hose points downward in effort to keep external junk from falling into the opening.

BTW when I dropped the tank to install the relocated 5/8 vent, I found the inside to be clean- mine had the small original tubes still in place and my usage of the truck had been "relatively clean over the road ".

I thought I was the only one who used an external fuel filter as an air barrier. Should have known better to think that!

These can be really great trucks, but seems like it requires a dedicated owner AND ACCESS TO THIS FORUM in order to get all the little kinks sorted out.

 

[steved]

Keep in mind, this only affected (mostly) the 03 and 04 trucks (and a few 05s). Most of the later trucks had the hoses installed at the factory... but I want to remember a few people stating they were missing on a couple 06s as well.



The primary purpose of those hoses is for emissions in the gasser-equipped models... they have nothing to do with a CTD. While they do allow the vacuum to bleed off the tank, the filer cap will also serve this purpose... those fittings are not needed. If you overpressure the tank, they will leak... I was lucky and mine stopped leaking once I pulled a vacuum on the tank again (shut my aux tank off for a little while).



For the record, I did this mod early on... tee'd the fittings to a 1/4" line and then into a small clear filter... it would surprise you how dirty that filter is after almost 200k.

 

[Super Briar]

I have an '09 & I didn't have the vent hoses on my fuel tank. There was a discussion on this over on the Dodge Cummins forum Check Your Fuel Tank Today - Dodge Cummins Diesel Forum



SB

 

[MChildress]

I really believe this was the culprit in the premature lift pump and injector problems. I am one of the ones who put fuel lines over the nipples and two small fuel filters into a hole in the frame rail. I have had no injector or lift pump problems.

 

[d6c]

What I don't get is why some rigs have hoses and others don't... My 07 didn't come with any... is this some poor quality control at the factory or does DC intend it to be this way?