[stephen low]

Paul

I didn't indicate in this thread but I'd previously talked about my fabrication of an "H" connection into my plumbing to overcome what you are describing.

The system on the AU engine, and I suspect any comparable system, requires continous flow over a water temperature sensor providing feedback to the ECU.

The "H" allows return flow whether the heater tap is open or closed, essentially what your four leg tap is for.

I have seen these in the past on ebay so they are out there.

Rob

I realised I'd moved the photos in my bucket account so you'll see they are reattached now.

Thanks & Cheers