2001 S-10 Vortec

I have a sloshing kind of sound when I start out and if I don’t use my A/C, (live in S. Florida) steam which stinks comes out of my air vents. Smells like burnt water and antifreeze. Dad changed two heater hose thinking it was a leak because we hear and smell one as soon as we stop, turn off truck and open up hood, but it is not the A/C run off. Falls close to where A/C run off is, but when looking under truck it’s wet I guess it’s the area directly under the engine. I am thinking of emailing a picture it!

So is it the heater core? I don’t use heat, can’t it just be disconnected? And what is that sloshing of water also?