The auto-shutoff valve is allowing too much fuel to get into the Mazda6’s gas tank when filling up. With a large enough temperature change the fuel can expand, pass into the charcoal canister and eventually drip out of the vapor vent line. Whether it’s a drip or a splash – once fuel starts spilling out and coming in contact with hot surfaces, it’s a very bad thing.
Luckily, Mazda engineers have come up with a countermeasure to reduce the amount of fuel that can enter the tank before the auto-shutoff activates. Bring the heat, El Niño.
The issue affects the 2014 Mazda6 with the 2.5-liter SkyActiv engine – about 19,000 vehicles in total.