Q: Heater Core? on 2007 Toyota Yaris

Rookie cbe0621eac06868b3efe0d8d1d3611e23c60d3114864ea2ec19a68cfbd3eebab
I have a 2007 Toyota Yaris yesterday while I was driving I heard water splashing in the dashboard I continued to drive to try to figure out what was causing it as I made a left turn cold water splashed on my foot. The passenger side was soaking wet as i returned home. I went out to the car this morning to look under the hood and I was totally out of coolant I filled it up and went for a test drive around the neighbor and heard no splashing sound. A mechanic friend of my told me it sounded like the heater core went out. Please help
(1) Answer
The only problem is - not sure where the cold water would be coming from if you had a leaking heater core! That water is very hot, steaming, and sweet smelling (like coolant).

I think what you experienced is an overflowing plenum full of water from the evaporator that cannot drain for some reason. Not sure though about your empty cooling system though and how that figures in.