graham@his.com.puter.INVALID (Graham*W) wrote:

>It was the fuel tank breathing in and the
>pressure (vacuum) relief thingy caused
>the sound. Hint - almost completely
>close the back of your throat and now
>breathe in with effort - you'll get a
>similar noise!

Sounds like a plausible explanation for the sound I'm getting. Do you
know if this is something that's considered 'normal' and nothing to
worry about?
Thanks for the response!