Could have blown up both the car and the house.

Those vents work well when they are working. AND NOW an annoying story from the old days

Many of you may be aware (codes may have changed) that any electrical/ combustion/ ignition sources in a garage must be 18" above floor level

Back in the day when I worked for a large industrial/ parts store here, "everybody" was hanging saddle tanks on pickups. Guy came in, wanted to know what he needed, I showed him electric and manual valves, explained he must check for a return system, totaled up an estimate of filters, clamps, hose, etc. and he thanked me and left

Some time, weeks? later he came in and waited for me, told me "what" and "did I remember him? "Yep" So he bought some fuel system parts and a changeover valve and then "confessed"

Says he "saved all this money" cuz he teed the two tanks together went down filled it up and parked it in th garage. He said he went out there later and THERE WAS FUEL ALL OVER THE FLOOR. The thing is, he said, there was a gas water heater in a corner closet and NEITHER of us could believe that thing didn't go sky high!!!

(One tank was slightly lower, he had filled up both, and one siphoned into the other and ran out the vent)