Re: gas tank pressure?

Posted by Owen_Dyneto On 2014/11/29 0:10:42

Dave - are you absolutely certain it was a release of pressure you heard and not the sound of air rushing into the tank? Without a vented cap you'll create a vacuum in the tank, I've seen cases where it's enough to actually begin to collapse the tank. It's pretty hard to conceive of a practical situation where the tank would pressurize as you've described.

Funny story. I had a friend with a 57 Plymouth. He filled the tank and lost his gas tank cover so he installed a non-vented cap, not knowing the difference. Drove a couple of hundred miles and refilled - it only took a few gallons so he thought he was getting 50 or so miles per gallon. Drove about 50 miles and ran out of gas. The tank had collapsed top down nearly to the bottom and also sprung a couple of leaks at the seams.