1997 GT 4.6 losing coolant with no puddle

[Konstantine]

I've got a manual 1997 Mustang GT with 120,000 miles. I've done everything I could so far, but I can't figure out exactly where the leak/loss is coming from. When I first got the car, the coolant was brown and I got it flushed a few times by a local shop, it remained brown but it is not sludgy or anything it is just a liquid. It started out with me just losing coolant level, during the summer months I would fill the reservoir with distilled water whenever it would get low, but as the weather gets colder, I've had to switch to diluted antifreeze. Recently, I felt wetness at my feet behind the wheel, and it turned out coolant was spilling right on my feet! My mechanic friends suspected it to be the heater core leaking, so they helped bypass the heater entirely by disconnecting and connecting a few hoses with an adapter. The coolant level is still going down after a hard drive. Also of note, there is a loose hose not connected to anything coming from the firewall that my friend believes to be an A/C water drain, that coolant had been coming out of previously. I also discovered that my coolant cap is making a hissing noise when i look under the hood with the car off, I don't know if that is normal. My oil cap is not milky and my oil looks good. My temp gauge doesn't work, but a local shop ran the operating temp at 220f so it shouldn't be overheating. Thanks for the help.

EDIT: I think i've posted this in the wrong section, sorry guys i''m new to the forum.

 

[B.mad]

Unfortunately, i don't know too much about modular. However, I don't believe the coolant comes out of the a/c drain if thats what it is. It could be that they might have not connected the hoses right. I know on my pushrod, its leaking from the timing cover gasket every once in a while. Pushing out all that sludge might have exposed a bad gasket somewhere. But that hose sounds like its coolant related and not AC related. I would start there.