TB over heated the other night. Wasn't bad. Wife was driving, luckily she's a gauge watcher. She immediately pulled over and shut engine off. It 5 miles from house so let it sit over night. Next morn took gallon jugs of water filled over flow to cold mark removed radiator cap poured a little water in there started it up and continued filling radiator. Let it idle to temp put cap back on and drove it home. Let it cool down and see coolant puddle behind right front tire and over flow tank empty. I have removed everything to get tank out thinking it was leaking. Nothing obvious to indicate that but the tank was empty. I removed radiator cap and there's fluid up to filler. Why is overflow tank empty is what I'm trying to figure out? I have found in other post info on HCV going bad and this is what I'm thinking now. In your experience with this problem was your overflow tank empty? Is it because as engine cools overnight and HCV (if that's prob)leaks coolants a vacuum of sorts is created and pulls fluid from tank to radiator?