Gas leak - Impala Tech
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post #1 of 4 (permalink) Old 07-30-2013, 05:26 PM Thread Starter
Join Date: Jul 2013
Location: Ashburn, Virginia
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Gas leak

Hi guys, rackin up the posts I have a 66 Impala, and on hot days gas pours out of the vent tube and their is a lot of pressure in the tank. I currently have a non-vented gas cap per spec, any suggestions on resolving the issue?

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post #2 of 4 (permalink) Old 07-30-2013, 07:26 PM
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A 1966 used a vented gas cap. Non-vented gas caps weren't introduced before 1972 when the charcoal canister first appeared under the hood to hold all of the gas tanks evaporative fumes between the times the engine was running. Your car needs a vented cap to let air in (it also lets gas fumes out; which is why they were banned in California first), but that technology hadn't been invented yet in 1966.

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post #3 of 4 (permalink) Old 07-30-2013, 09:49 PM
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Make sure your vent tube that goes up into the trunk and back out isn't plugged or bent.
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post #4 of 4 (permalink) Old 07-30-2013, 10:53 PM
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1965-1967 used Non-Vented gas caps and had the vent on the tank itself. The full size cars with these gas tanks would spill gas out the back under acceleration if they were vented. Previous Impalas with side fill tanks were vented.

Make sure your vent is not plugged.

64 Impala SS 327/300 survivor
67 Impala SS 327 triple black hardtop
67 Impala Bench Seat 4 speed
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