MichaelKlein

So mine ended up being the same thing. Finally last weekend, after it began overheating more frequently, I jacked her up and checked the coolant pump vacuum line...sure enough, coolant came flowing out. So trucked her over to the Porsche service where they repro'd the problem. This will be the second replacement water pump she has had now - and apparently now its a newer better version. All in all they replaced the water pump, the valve block, all vacuum lines, and the vacuum pump under warranty. While she was open I had them also do the serpentine belt for a little extra.

So it turns out, when these water pumps start to go, they can be quite intermittent and unclear to immediately diagnose - similar to your situation too - but eventually it becomes obvious. But glad it seems to be fixed now.

Schoi78

"Water pump is vacuum operated on 991.2, if you want there is a 90 degree vacuum hose right below the water pump. Unplug it, does coolant pour out, there should be zero."

Just out of curiousity, Is this the 90 degree vacuum hose you are talking about? pic just for reference: https://cimg0.ibsrv.net/gimg/rennlis...c9c79e6c1.jpeg


If coolant pours out, then what would be the diagnosis?