I have lost all the coolant out of my 1997 VW Golf 2.0L car. It has leaked out from the passenger side of the firewall. Is this a heater core issue? I pulled over on the side of the road when it started to heat up and shut it off. The coolant puddled on the ground on the passenger side. I added more coolant to the overflow and it ran right out the firewall. I started the car to move it a bit more off the road and a big puff of white smoke or steam came out of the back end. The oil is fine, not milky so I am certain it isn't a head gasket. Car will start but the coolant just runs right out from the firewall area. Please help! What hoses run through that area or could it be the heater core?