Date:         Sat, 4 Nov 2000 15:11:12 -0800
Reply-To:     Dave Bayer <daveb@CP.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Dave Bayer <daveb@CP.NET>
Subject:      Re: charcoal filter
Content-Type: text/plain; charset=us-ascii

> I believe you are referring to the vapor recovery canister. The canister is
> full of activated charcoal. It is designed to recover fuel vapors and such
> which would otherwise escape into the atmosphere. They last for years. Don't
> exactly know how long. Perhaps someone else can answer that question. I have
> vehicles that are 20 years old which seemingly still has working vapor
> recovery canisters.

        The activated charcoal eventually will get saturated though
and will stop absorbing vapor. It's not actually easy to figure out
when it saturated though - you might try sniffing the vent
tube from it. If it smells like gas it needs to be replaced if you
care about releasing aromatic HCs into the atmosphere. If you don't
care about your HC pollution, then you needed worry too much.

        I suppose the charcoal canister once saturated could become
explosive (with a mixture of oxygen and gasoline fumes though I'm
not exactly sure how much oxygen would be in there). Not sure if
there is much of a way to actually reach the flashpoint in the
location that the canister is mounted in though. I think the
Bentley recommends this be changed every 30,000 miles or so, maybe
it was 60,000, my bentley isn't handy. It is really a time based
thing though like brake fluid.

dave