Gerry, I traced my leak down to the core itself.  The bleader screw was
water tight, the rubberr that seals the ends of the core is rotten (flakes
away with your fingernail!!!!)

I removed the core and bypassed it with two CPVC elbows and a piece of
heater hose, it works fine for now, but I might have to find a new one once
it starts getting COLD around here (Wisc.).

>From the pictures in the manuals the rear core seems to be the same (maybe,
I'm only hopeing here!) as the heater core in your avarage Golf.  You might
not be able to turn it off... well change that thought, if you also got the
thermo-valve from the golf you could make it remote control!!!!

I'm rambling, but the bottom line is, mine was leaking, BAD!