The other day it was a cold so I started my wife's 07 Expy to let it warm up for 10 minutes. When we went to leave I could smell anti freeze in the truck. The truck wasn't over heating, there were no puddles underneath it. I opened the hood and there was no obvious leak anywhere. The only thing I noticed was a spritz of droplets all over the intake cover and other black surfaces were it stood out. It was as if the engine had sneezed out some anti freeze, but no visible sign of where it might have come from. It's running fine and hasn't done it again since. Anyone want to take a guess?