You can get a fair (tablespoons) amount of water as condensation in a
cool exhaust system, don't panic too soon.  I don't know if you'd be
able to see the coolant color in antifreeze that has been through the
exhaust system or not -- but check it might answer your question . . .

If you just want to be sure you could pull the stud you fixed and put
some sealer on it.  I think that might fix a small leak.

Doug

>I think I may have penetrated the water jacket when repairing the =
>stripped exhaust header bolt holes on the head of my 1.9l wasserboxer a =
>few months ago. Next steps? remove the headers (again ugh!) and =
>determine if I can visually make out where the leak is. Failing that =
>drop the engine for a better look or maybe pressurize the coolant system =
>and see where it is leaking? Any suggestions welcome.
>
>Here is the detail of the goring I managed -
>
>After successfully (thanks to the fine people on this list) repairing =
>stripped threads securing the power steering pump I got bold and went =
>after the exhaust header bolts with the engine in. There was just enough =
>room to fit the drill in there. The new threads went in fine and the =
>exhaust was amazingly quiet. I left for a trip into the hill country and =
>drove all weekend without incident. The van sat for a while as I worked =
>through replacing the ac lines. When I started it up quite a bit of =
>water came out of the exhaust pipe. Not good. Enough water to puddle the =
>driveway. The engine ran fine and the plugs weren't fouled or rusty =
>leading me to believe that the penetration happened only on the exhaust =
>side.=20
>
>84 Westy 1.9l wasserboxer
>Owen Brand