the core is what I find leaking usually.  Quite common.

On 3/3/2013 11:51 AM, Finn Runyon wrote:
> Our van is nearly ready to hit the road after a year's work to rebuild the engine.  I bought this one with a blown engine.  The rear heater os leaking, and I am wondering if the valve tends to leak, the O ring, the core?  If there is a most common failure I will do that or do generally rebuild the whole unit?  The valve defiantly is leaking.
> Thanks,
> Finn Runyon
> 87 Westy Roo
> 89 Westy Pooh
> 12 GTI Autobahn