Coolant Leak; 91 190e 2.6

[tjh]

I've searched the forum and read a few things about this problem but am unclear about symptoms I'm seeing.

Coolant drips under dash onto my ankle, and coolant leaks out of drain pipe on driver's side beneath door area. Most of leakage is from this pipe. The drain pipe on passenger side is moist, but most drainage appears coming from left-side pipe.

Losing about a half liter daily.

Looked under wiper assembly, saw no moisture under there. No apparant leakage in engine compartment.

When I remove cap from coolant tank, it seems to be unpressurized, although that is new. It leaked even when pressurized before. However, leak flow has increased substantially since apparant depressurization change.

Where does that drainpipe originate? Since most drainage comes through there it would help knowing where it starts.

Since it's also dripping under the dash, left side, I wonder if it's the core, but since most comes via the drain pipe, I wonder what the alternative could be.

Broken heater valve? Is that under the wiper assembly?

Leak in water hose connecting to core? If so, that's inside the cabin eh? So why leak through the other drain hose? ...

Tips, tricks, diagnostic hints? I'm REALLY wanting it to NOT be the heater core for obvious reasons.

Thanks in advance!