Low Permeability fuel tank question

[JGator]

What is possible to be done with these Low Permeability plastic tanks in the summer? These things swell like crazy in the sun. I usually leave the cap slightly open to let them bleed off pressure that builds up. I've seen the piece that goes in the line to keep the pressure from pushing too much fuel to the motor, but do those remove the pressure from the tank too?

 

[airshot]

I have done the same thing my neighbor did and that was to remove the fill cap and take out the gasket inside, drill a very small hole thru the gasket and then drill another very small hole thru the cap but on a different radius than the hole in the gasket so the two holes will never line up. This has proven to allow the pressure to bleed off but not allow liquid to escape. Do not know about your tank but it works on mine and my neighbors plastic tanks.

 

[JGator]

I have done the same thing my neighbor did and that was to remove the fill cap and take out the gasket inside, drill a very small hole thru the gasket and then drill another very small hole thru the cap but on a different radius than the hole in the gasket so the two holes will never line up. This has proven to allow the pressure to bleed off but not allow liquid to escape. Do not know about your tank but it works on mine and my neighbors plastic tanks.

This I will have to try. One of my tanks is the old type, lets air in and pressure out through a valve on the cap, pre dates low-perm type. The other two are low perm types, one has a one-way valve built into the cap that you cannot see from the top of the cap and the other has an adjustable valve in the cap you can see and can open and close. You have to open to allow air in and can press down to release the pressure.

Jim