Gas tank issues
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Tuned
Joined: Oct 2016
Posts: 255
Likes: 2
From: South dakota
Gas tank issues
Is the gas tank on a 73 f 250 Vented? Because when its especially a warm day and you remove gas cap there is alota pressure built up in tank. is this Normal? I replaced the gas cap with a new one and it will allow air to enter tank but not let it out. sometimes if the tank is pretty full and you remove the cap it will puke out some gas.
Hotshot
Joined: Feb 2004
Posts: 10,756
Likes: 2,588
From: The Shenandoah Valley
Yes, it's perfectly normal.
Just like the gas in cans out in the shed, it'll build pressure in a gas tank. A good amount of heating goes on there. Many gas caps, like the Carquest 10749 I just bought for my '77 have two extra tabs to keep the cap from suddenly blowing completely off on an unawares operator getting ready to fill up. Just a few psi, even less than your fuel pump pumps to the carb inlet, will create quite a swoosh when there's suddenly 19-20 gallons of volume of such pressure suddenly released.
I was thinking mine had a leak when it quit swooshing, was a cracked gasket in my fuel cap.
A bad gas cap can loose up to 20-30 gallons of gas due to evaporation in a year's time.
Just like the gas in cans out in the shed, it'll build pressure in a gas tank. A good amount of heating goes on there. Many gas caps, like the Carquest 10749 I just bought for my '77 have two extra tabs to keep the cap from suddenly blowing completely off on an unawares operator getting ready to fill up. Just a few psi, even less than your fuel pump pumps to the carb inlet, will create quite a swoosh when there's suddenly 19-20 gallons of volume of such pressure suddenly released.
I was thinking mine had a leak when it quit swooshing, was a cracked gasket in my fuel cap.
A bad gas cap can loose up to 20-30 gallons of gas due to evaporation in a year's time.
