I have a coolant leak coming from what appears to be some kind of valve or sensor that the coolant hose runs through before going into the firewall. Would anyone know what this is for and what it's called. The leak is pretty bad and I want to replace it.

Thanks

 

That is the heater control valve, turns the coolant flow to the heater core off and on. You could bypas it altogether if you don't mind the heat on all the time.

 

Thanks for the info. The van is just my winter car so I don't mind the heat on all the time at all.