Originally Posted by Jhill

Come on your at Porsche now, time to throw that funnel in the trash where it belongs. Get yourself an airlift kit or similar (I use mityvac mv4525, most complete cooking system tester I've ever used). Truly the only way to get all air out of today's engine with all their crossover passages etc etc. Japanese still seem to design systems that are easier to bleed conventionaly though.

One thought is there are two designs of the z cooling system. One uses a conventional expansion tank system and the later (I think 2012) use the tank as part of the pressurized system. If you have the later there is usually a upper return hose (I'm not at my car or looking at it currently so I'll have to verify this later and hopefully not look stupid) the return hose should have a pretty steady stream of coolant back to the reservoir. This was always a good indicator for when the plastic impeller would break on 1.8t vw engines.

Oh and ps just kidding about throwing the funnel away, keep it as the taper hole is much easier to secure the block checker in than some radiator openings, but that's really all I used it for after having a vacuum fill. Also on subject of block checkers there are different designs and the ones with two chambers are much more sensitive to very small gasket leaks (second chamber will change color)