Gas tank becoming pressurized???

[C5GTO]

Originally Posted by sunman

This is a Classic Roadsters tank and filler neck. The LeMans cap has a fuel drainback line too. Plugged maybe? Fuel and return line are in the sender unit. If you don’t have one good time to add it.

Yes, this is the style of CRL fuel tank that's in the car and the same style of vented fill that the LeMans cap is mounted on. I believe it's the location of the fuel fill pipe in the vertical middle of the tank that causes fuel to rise up to the fill cap when the tank becomes pressurized. That is unless the tank is less than half full. When I was checking to ensure the vent line was clear, I could make fuel rise up in the fill pipe simply by blowing on the vent hose with my mouth.

Overall, I think the location of the fill pipe in the tank is a poor design but I'm not inclined to change it at this point unless there's a real pressing issue that can be resolved by doing so.