Heater Hose nipple

A regular 1/2" nipple isn't going to fit in that hole. The factory had a special fitting that was tapered.

5/8" nipple on left
1/2" nipple on right
factory tapered nipple in the center(for 1/2" hose)
[URL="http://i137.photobucket.com/albums/q229/burdar/Misc/51112001_zps4c81bfab.jpg"][/URL]