Gas tank pressure, venting question. Need advice from Gurus

cdherman · Post by **cdherman** » April 24, 2007, 4:29 pm

OK, there was a thread a couple of weeks ago about pressure build up in gas tanks and it never exactly got answered.

Its clear that the gas cap vents to prevent vacuum build up in the tank. But what about pressure?

What was original? Vented one way or both?

I cannot get the fuel line to seal and before I give up on that, I want to be sure that I have the right gas cap.

Thanks.......

66fordtrucknut · Post by **66fordtrucknut** » April 24, 2007, 4:43 pm

CD, If you take your cap off and shake it, it should rattle. I bought a new one and it was building up pressure. At ss2 someone asked if I had the right cap. I took it off, it did'nt rattle, whacked it on the curb, bingo, I guess it was stuck. I don't know whether this is correct info. but it worked for me.
Charlie

ras4434 · Post by **ras4434** » April 24, 2007, 5:55 pm

FWIW: The two I have that are currently running would run with or with out the caps on. One has an aftermarket cap and one is what I believe to be original. They twist on and are tight but definately vent because I have had gas run out on a hot day when parked leaning the wrong direction. Never had what I would consider to be a pressure problem. Just my experience, good luck.

blackagatha · Post by **blackagatha** » April 24, 2007, 10:56 pm

Sometimes in the summer, the vapor pressure builds up so high in my truck that the seal lifts up and the pressure lets loose in a loud squeal. It seems ridiculous, but it seems that this is just the way these trucks are. I wish the tank had an overflow barf can like a radiator, with a vent line from the top of that... that would be slick.

I'm pretty much sick of the cab tank and some day want to build myself a big tank/ toolbox in the front of the bed.