Whenever I open my gas cap, it sounds like I have just opened a black hole.

Almost like I have I have to be careful that I am not sucked into the void I just

created. I was thinking about that today as I was pumping gas and wondering

if a vented gas cap would be better. Mine is a non-vented gas cap. Interestingly, 

of the ideas I had was to drill a small hole in the cap for pressure relief. I figured the

engine would be able to more easily drink fuel like it needed to without having to suck

really hard in order to get it. I did a search in the forums and came across this post.

Can someone please explain why drilling a small hole in the gas cap would be illegal?

What does it do that would cause concerns? The only thing I could think of, there

would be a small amount of fuel vapor leaking out. I would suppose if I were parked

in a parking lot and someone parked beside me with their window down while smoking

a cigarette and the wind was blowing the right way when they flicked the still lit

butt to the ground, that vapor could ignite. Is that why drilling a hole would be illegal

or is there some other reason? 



I read that you should NEVER under ANY circumstances

drill holes in your gas cap. Now I'm not the EPA, but I

believe its also illegal in the US to drill holes like that.

If you buy a new cap and still get the smell, buy new

hose clamps for your fill pipe connection. They're like

$4 and should fix your smell problem.








Originally Posted by flash

A new gas cap didn't do squat on mine.  I even tried drilling a hole through the top as I read in the forum that one member put  on a vented cap and it fixed the problem.  If I keep it below 1/2 tank at all times there is no problem.  Has got to do with something about the fule slushing over a certain point in the tank or filler neck and only when crankin' a hard left.


I think that's the way these little buggers like to jerk our chains now and again.  By throwin' us one of these.....figure it out if you can deals!



1973 Superbeetle (California Edition)
Personally-built 1600cc Aluminum DP
Pertronix Ignitor EI and Flamethrower Coil
Taylor Hi-Perf plug wires
Billet oil filler
Urethane suspension bushings
Stainless Braided brake lines
Color-matched brake drums

72 Super Beetle
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Hi Guys,

Well many modern cars can make that sound when the cap is taken off..

as the fumes are sucked into the engine with the gasoline..

My 19689 Beetle's cap isn't vented as far as I know, I have a small breather hose that is supposed to attach to a long plastic tube behind the dash and another small hose goes next to the front tire and a pipe [pipes] the fumes under the front of the car...  I just left the long plastic thing off...

One day I was filling My car, and I noticed fuel pouring under the front of the car, thru the breather hose. as I didn't have it high enough...

I know have that small hose going up about 4 inches above the top of the fuel tank, so that shouldn't happen again... Gas was around $1-36 a liter when that happened too...

but If You do have that sucking sound...   a small illegal hole may fix the problem...  most fuel tanks should have small breather hoses going somewhere...




Lee Noonan -- 68AutoBug -- Australia --



68AutoBug - helping keep air cooled Volkswagens alive in Australia & around the World -
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