I actually took my own advice from the Stop Leak forum in General Discussions, put $3 worth of Barbs Stop Leak Heavy Duty (the one with the pellets), and by the time I got home from the store where I put it in, the leak had stopped. Let it run for 30 minutes, cycling between heater on and off, and shut it off. Not a drop leaked out.

Told my friend he has to do the timing belt soon anyway, so when hes that deep into it, spend a bit more time and take that intake manifold off and get to that hole for real. Or if its as good as my previous stop leak experiences, itll be fine for years.