1. Is the tank actually being pressurized? If all extra vents are blocked then the tank is isolated, with the gas outlet/return being the only exits for pressure.
2. As the fuel is siphoned out the tank is not pressureized, it's reacting by producing a vacuum.
3. The noises you may be hearing is the outside atmospheric pressure acting on the now depressurized tank. The metal is actually being flexed by the atmospheric pressure much like the hull of a Submarine when it deep dives.
4. Why not run one vent line to a charcoal canister and then from the charcol canister to the pvc output line?
2. As the fuel is siphoned out the tank is not pressureized, it's reacting by producing a vacuum.
3. The noises you may be hearing is the outside atmospheric pressure acting on the now depressurized tank. The metal is actually being flexed by the atmospheric pressure much like the hull of a Submarine when it deep dives.
4. Why not run one vent line to a charcoal canister and then from the charcol canister to the pvc output line?
