Tank Pulling A Vacuum/Pressurizing ?

[Worstenemy453]

When i run on my rear tank for a little bit and then go to fill it up it will either release or suck in air as soon as i open the gas cap. Kinda like when you open a tennis ball can. I haven't figured out if its sucking air in real quick or pushing it out real quick but my front tank doesnt do it. Is this an issue ?

 

[FordGuy100]

Mine does that too, when I take the caps off. I have no idea if its supposed to or not.

 

[Worstenemy453]

Only my back tank does it which leaves me wondering. If they both did it, then it wouldnt bother me.

 

[Dsl_Dog_Treat]

The rollover valve has a 1/4 line to it that does allow the tank too vent so it doesn't draw a vaccum.

What happens 99.9% of the time is them dang pesky mud dauber wasps lay their egg in the end of the vent tube and mud it shut thus plugging the tanks only means to vent.

The vent tube if unmolested will come off the top of the tank and terminate up to the frame rail drivers side.

 

[Worstenemy453]

The rollover valve has a 1/4 line to it that does allow the tank too vent so it doesn't draw a vaccum.

What happens 99.9% of the time is them dang pesky mud dauber wasps lay their egg in the end of the vent tube and mud it shut thus plugging the tanks only means to vent.

The vent tube if unmolested will come off the top of the tank and terminate up to the frame rail drivers side.

Could that effect the way it runs on that tank and can i access that vent without dropping the tank.

 

[LCAM-01XA]

Yeah you can access the vent, Ron ain't talking about the rollover valve itself, just the end of the rubber line attached to it - that's on the inside of the drive-ride frame rail IIRC, before the crossmember the tank straps attach to, pretty much right above the axle.

Alse, on your other question, yes sometimes this can affect the way the truck runs - mine don't, several others reported issues in a thread from a month or so ago. I actually pulled my o-rings on the caps and that solved my venting issue, in your case tho just check the rollover valve vent tube like Ron suggested.

 

[Worstenemy453]

Yeah you can access the vent, Ron ain't talking about the rollover valve itself, just the end of the rubber line attached to it - that's on the inside of the drive-ride frame rail IIRC, before the crossmember the tank straps attach to, pretty much right above the axle.

I will look for it when i stops raining. I usually only use my rear tank once a week or so and keep it filled for when my front tank gets close to empty. Neither one of my gauges work right.

 

[Dsl_Dog_Treat]

Could that effect the way it runs on that tank and can i access that vent without dropping the tank.

Yes and yes.

The tank is vented thru the rollover valve. Guess I should have added that in there.

 

[icanfixall]

I concur with what Ron has posted. Time to get wet and find out whats plugging up the vent time.

 

[Worstenemy453]

If i fill my rear tank completely to the top and then not use it. When i go to fill up, the rear tank will still want 2 or 3 gallons to get back to where i filled it. Is this normal too ?

 

[Dsl_Dog_Treat]

If i fill my rear tank completely to the top and then not use it. When i go to fill up, the rear tank will still want 2 or 3 gallons to get back to where i filled it. Is this normal too ?

Well if the tank isn't leaking then thefirst thing that comes to mind to cause that could be that the foam from the prior fueling has settled allowing more to be added.

Unless the FSV isn't completely switching over allowing a partial draw from that tank.