Antifreeze in oil!

Nice site!
Has anyone had antifreeze get into your oil? When I made the last oil change the oil had what looks to be antifreeze in it (maybe gas?). I figured it came from either the water pump or one of the heads. My problem is finding a leakdown tester that fits the Hawks 12mm plug. All the testers that I have found only work with 14 and 18mm plugs. The nearest Honda dealership is 70 miles away and I would prefer to do the work myself. Anyone else have this problem? Any suggestions would be appreciated. Thanks!!