You misunderstood. In the air cooled Vanagons, the heated air for
passenger comforter is passed up to the front of the vehicle by duct
work. The saddle in the gas tank accomodates that duct work.

Of course my experience in an aircooled beetle was that the heat
exchangers rusted up so quickly you got into a situation of either
never having heated air, or permanently having heated air...On buses
or aircooled vanagons (I've never owned one) I understand that the
heated air sometimes wasn't by the time it got up to the front. Even
on working systems.

On Sep 22, 2006, at 12:20 PM, Todd Last wrote:

> GoWesty writes....
>
> " Interestingly, the depression down the middle was put there to
> allow the hot air duct to pass from rear to front on air cooled
> Vanagons. Even though there is no purpose for it now, and even
> though 90% of all Vanagons ever produced were water-cooled, the
> fuel tank design never changed. Go figure
> ."
>
> Is this true?
>
> I thought all the cooling air came through the side vents at the
> rear of the van...
> and if this is necessary... why did none of the type II vans have it??
> Seems a rather suspect explanation to me...   If anything, I
> thought it would be there to help the air exit after the radiator
> for the water cooled models.