Earlier this week I posted a query about a coolant leak from an invisible 
crack in one of the heads on my '87 Westfalia. It seems that a couple of 
other listmembers have experienced the same problem. Similar leaks at 
exactly the same location: on the top of the right head, just below where 
the #5 stud is capped. Both were cured with BarsLeak or similar coolant 
additive process. I'm going to first try to patch it from the outside with 
thin layer of a product like JB Weld. This is a putty-based epoxy compound 
that can be applied to wet surfaces. I experimented with it on a rear heat 
exchanger and think it may work here if it will withstand the temperature. 
I'll let you know how it works.

-Mark