this is on a 2003, 1.8, bone stock
This is a pretty serious leak, caused an overheat on the highway and I'm worried might have damaged the head gasket although that isn't clear yet.

I went all the way to UV dye in the coolant to find the culprit and even that isn't giving me useful info
I did a video showing the coolant leak as far as I can see it. It seems to literally spring from the starter motor housing, or if it's coming from elsewhere it's insanely hard to tell where
Video, which hopefully works
I pretty much never ever consider this but I may need to give it to a shop to find the leak faster and more reliably

 

heater hoses? Mine are on the other side, but lhd ... ? Or the oil heater lines?

 

My guess is either the coolant hose to the oil filter housing, or the rear coolant outlet gasket.

 

This is my guess too.

 

My small coolant hose running from the back of the head on the passenger side to the oil filter area was leaking. The actual leak was at the rear connected to the barb. The heat from the EGR pipe finally dried that end out out, coolant leaked, dripping on the underside of the hose. It travelled down that corner bend right above the starter too.

 

reading that hose is referred to as the "devil hose" isn't filling me with confidence

however, the part numbers (for my reference) are
BP4W-15-536A - the hose from the oil cooler to the back of the head, and
BP4W-13-681B - the hose from the throttle body to the oil cooler.

the rear coolant outlet gasket is something i'd also like to not do

guess i'm buying some 45 and 90 degree pliers on amazon

 

They're really easy with the intake manifold off. If you don't want to do that, removing the alternator allows decent access back there for a hand. If you have AC or a reroute, there's less room between the frame rail and intake manifold than you'd think.

 

I had a 1992 that I purchased with a similar issue, it turns out that the freeze plug behind the started fell out. Was laying on top of the starter. $0.69 later it was all good.