The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - Help! Pressure Build-up In Gas Tank

**pjmoreland** · 01-18-2005, 04:44 PM

The gas cap I have on my truck is a Stant 11623. It's the one that has (had) the one-way check valve in it. It was not letting pressure out of my tank. If I remember correctly, the Stant catalog they have at the auto parts store doesn't even list a gas cap for 1967. I think the earliest they listed was 1969 or something like that.

Here's what is said on the partsamerica website about a Fram gas cap for 67 Chevy:

"Keeps fuel from evaporating. Keeps contaminants out. Keeps fumes in (EPA regulated). Slowly releases pressure from the filler neck prior to cap's removal to alleviate the problem of fuel expulsion."

I don't see how the pressure can get out if the fumes can't get out. I can see why the 72 trucks have the evaporative emissions canister connected to the extra line going to the gas tank.

01-18-2005, 04:44 PM	#3
pjmoreland Senior Member Join Date: Jan 2005 Location: CA Posts: 6,236	The gas cap I have on my truck is a Stant 11623. It's the one that has (had) the one-way check valve in it. It was not letting pressure out of my tank. If I remember correctly, the Stant catalog they have at the auto parts store doesn't even list a gas cap for 1967. I think the earliest they listed was 1969 or something like that. Here's what is said on the partsamerica website about a Fram gas cap for 67 Chevy: "Keeps fuel from evaporating. Keeps contaminants out. Keeps fumes in (EPA regulated). Slowly releases pressure from the filler neck prior to cap's removal to alleviate the problem of fuel expulsion." I don't see how the pressure can get out if the fumes can't get out. I can see why the 72 trucks have the evaporative emissions canister connected to the extra line going to the gas tank.