After starting the newly installed engine in my 2000 Boxster S I found a fairly serious oil leak coming from the oil cooler, my first reaction was o-rings, even though I changed them while the engine was out. The engine was bought from a "recycler" so I have no experience with it.
Upon closer inspection I found this:
It seems to me if the o-rings were the problem the oil would be leaking out under the oil cooler and there would be no way it could collect in the "tray" that forms the bottom of the cooler where the bolts are. Also there is almost no oil on the top of the crankcase. I am therefore pretty sure that the leak is higher up and that I need to replace the oil cooler. I will do some more running to see if I can find the general area of the leak. Meanwhile can anyone see an error in my logic?