Assuming all things are as they should be - ie, fans work, coolant level
is correct and system properly bled of air, heat leves in proper
position - the only thing left I think is the thermostat. If the
thermostat fails in the open position, the engine will warm up to near
proper operating temperature as long as  you have the power applied, but
when coasting  or stopping for lights etc, it cools quickly and you
won't get much/any heat,

John Rodgers
Clayartist and Moldmaker
88'GL VW Bus Driver
Chelsea, AL
Http://www.moldhaus.com

David Prendergast wrote:
> Did a search on this but didn't find much.  84 Westy, heat seems to be
> working fine (although not as hot as I remember, although it could be
> my imagination) Whenever I come to a stoplight and reach down to feel
> the heat (front, havent checked the rear) its blowing cold until I
> start moving again.  Weird and wacky to me.  No coolant leaks and
> bottle is full.
>
>