What is the white exhaust coming out my 2000 Honda Accord EX V6 and what is it a...

[A.J. H]

...result of? I had a problem with the cooling system (radiator, thermostat and fan). All where running as if the car was hot but when I did a feel test over a couple weeks it didn't feel like an actual problem and most advised that it was a regulation (thermostat) error and it would be a simple fix. It ended up blowing the cap and gooseneck that holds the cap off one night and so I went about changing the coolant fluid and the thermostat. It appeared that the radiator was empty which I'm being told could've happened as a result of the thermostat not regulating properly. So last night I filled the radiator and started the car to get it circulating and it started spraying it all over so i shut it down. I placed the cap on and started it and it was fine minus the white exhaust coming out the back, something it never did before even with this current problem. So hear I am hoping that there is some savvy mechanic that can answer, not irrefutably, but at least plausibly what is afflicting my ride right now. It is a 2000 Honda Accord EX v-6