A fellow List Member requested this info about a block sealer that I have used
to seal up leaky heads with much success.  Here it is again if you are
interested:

I would NOT use Bar's Leak.  Why?  It messes up the heat dissipating qualities
of your radiator (translation: it coats your radiator with black tar and it
won't cool the engine like it used to.).   This stuff that I used is found in
racing and speed shops only.  It is called Moroso Ceramic Block Sealer.  It
usualy costs around $14.  It is ceramic (not tar) and when you smell it, it
smells like cement.  But it works excellent.  I had steam coming out of my
tailpipe 'cause the head gasket blew.  So I used this Moroso and it resealed
the heads without coating the radiator.  What it does is goes to the leak and
plugs it up.  Then you drain out the excess so it doesn't coat anything that
it isn't supposed to.  Then you let it air dry over night.  I used it and then
took a trip to Boston (I live in soutern New Jersey).  Then a couple months
later I took a trip to Georgia.  The stuff held up great for the four months I
ran the van with it (acutally it was the first time since I owned the van that
I didn't have to check the water level every time I stopped somewhere) and
never leaked again.  I sold the engine and am now getting ready to replace it
with a Golf motor (got all the stuff from a diesel Vanagon).  So I would
highly recommend using this stuff.  It is a temporary fix, but it has been
known to last for years!  Just look up "speed shops" or "racing shops" in the
phone book.  One of them will have it.  Have fun.
Ken Wilford
John 3:16