Hi Folks -

Any advice on getting the coolant crossover pipe o-ring to seal into the
thermostat housing on an '84 waterboxer?

I just replaced the thermostat, which due to frozen bolts required
removal of the whole thermostat housing from the block.  The crossover
pipe in question comes from the right side of the engine (viewed from
the rear) and ends in an o-ring that inserts into a bore in the
thermostat housing.  I've replaced the o-ring, and tried 1) no sealant,
2) Hylomar, and 3) silicone (Permatex), and I still have a slow
drip-drip-drip from this location.  The pipe itself is not in the best
of shape (rust pits, but mechanically sound), but a new one is a
long-lead special order at the dealer.

Any other sealant to recommend for this application?  New pipe?  Embed
the whole project in concrete...?

thanks,
Ed Mellinger
Monterey CA
'84 Vanagon

p.s. replacing the thermostat sure helped the running temp...
previously  the gauge would barely climb out of the warm-up zone on the
gauge... now it climbs right to midscale within a few miles, and stays
within a needle width No Matter What.  Exhaust CO went down from 3.5% to
1%, which was the point of the excercise (smog check), so I guess the
brain thinks it's warmed up too!