2nd Gen Non-Engine/Transmission Fuel Tank Leaking

[benhall]

So I was filling up the truck today and noticed that my fuel tank is leaking from screw on top of the tank where the gauge sending unit/fuel pick up/vent tube are located. Is there a gasket for all of this mess that could have gone bad or could it be something else?



Ben

 

[Jeff Knight]

There is a rubber gasket around the module. The cap might have come loose. It just screws on. I would see if it came loose. I just changed my module a couple of weeks a go. I've never had mine leak. Good luck with it... Jeff

 

[benhall]

I just got back in from checking the cap and it's tighter than tight. I did notice there is what looks like a vent or something that has a couple barbs for a tube. This thing faces towards the middle of the truck. I have never seen this happen after a fill up.

 

[WestTN]

Sounds like you are overfilling.

 

[benhall]

I filled it up the same way I always have, except there was a semi filling up next to me when I was filling up today. I guess I wait another 450 miles before I fill up again to find out if it will happen on the next fill up.

 

[TboneMan]

One morning last summer I made the mistake of filling up, diving home and parking the truck in the driveway all day (80+ deg air temp, driveway area probably much higher).



The place I get fuel is a little over 8 miles from the house.



I came out to a puddle of fuel under the tank. I figured the fuel in the tank expanded with temp. and pushed out the vent.



Hasn't leak a bit since (of course I don't leave the truck out in the sun with a full tank of fuel either).

 

[benhall]

I checked this morning under the truck and the ground was dry. I wonder if there was more air in the fuel than usual as I was pumping since there was a remote pump next to me running at the same time.

 

[JLandry]

Ben,



Odds are the roll over valve located on the top of the fuel tank module is what's seeping. This is the white plastic device you saw with the exposed hose barb pointing toward the center of the truck. Typically it can start leaking in a couple of locations: 1. Around the rubber grommet which the roll over valve pops onto the top of the fuel module, or 2. Through the roll over valve itself. In my experience, usually it's through the valve and not the grommet.



The roll over valve is supposed allow fuel vapors to vent from the tank to the atmosphere, but it also prevents fuel from leaving the tank if overfilled, or if the truck were to "roll over" in the event of an accident. It does this by means of a small check ball located inside the valve. Dust and dirt can accumulate inside the valve making it impossible for the check valve to seal, this fuel can seep out of this valve when the tank is really full.



One simple way to fix the problem without removing the tank is to attach an appropriate length of 1/4" ID fuel hose to the barb on the roll over valve, secured with a mini-hose clamp. Route and terminate the other end of the hose to a point higher than the tank fuel filler neck somewhere inside the space between the inner and outer walls of the truck bed.



Best regards,



John L.