Afraid of the answer.....

[911monty]

Here is a picture of the manifold from inside the engine compartment.

The small diameter hose at the top is the oil cooler connection. The middle I believe is the vent from the radiators (not sure since I've never followed it). The lower that you can see just below the bend in the metal piping from the middle hose is the drain hose. Hope this helps.




And yes a pressure test would of course been the proper thing to do, but hell you've still got a full day and may resolve this yet!