Does anyone have a diagram of the cooling system hose routing ?

Did you try the clean cardboard trick suggested above? That should narrow your search.

I know the area it is coming from but with everything in the way it is hard to tell exactly where it is coming from.

This with an ultraviolet light should help.
https://shop.advanceautoparts.com/p/...041-P&c3ch=PLA

A bit late, but on this engine the water outlet housing breaks every 40.000 miles. I am on my third one. It is located on the engine, where the waterhose comes out to go to the reservoir. 3 8mm easily accessible bolts, one for which you need a ratcheting swivelhead 8mm spanner.