It is a bleeder for the core, although I have never had to use it.  I guess
if your rear core wasn't getting hot you could try to bleed some air out
there.

Ken

On Tue, Jul 21, 2015 at 6:39 AM, Dennis Jowell <dennisjowell@gmail.com>
wrote:

> Does anyone know what that small white cap on the rear heater core does?
> 1988 Westy GL.
> I am working on changing coolant lines. I think it may be a breather for
> the heat core. My Bentley has no information .
>
> Dennis Jowell
> Scotch Hollow Farm
> Newbury, Vermont
>

--
Thanks,
Ken Wilford
John 3:16
www.vanagain.com