Thanks, but which one is going to the upper tunnel and which one is going to the lower one together with the cooling pipes?Left is supply, right is return when looking at it in this view, emerging from the tunnel.
Okay thanks a lot, both of you! So the supply is coming from near (or sometimes directly from) the waterpump? And return goes to the return tube on this picture?The front-most one is supply running thru the tunnel in the cabin. The rear-most one is the return. Maybe this additional photo helps:
View attachment 71474
EDIT: also, the supply side feeds the control valve. The return from the heater core (which is not visible in the photo) on these early X's is a tube.
Now all is clear to me. Thanks to everyone here!The heater supply comes from a fitting on the head just above the pump. On 1500s, the return is on the horizontal return pipe as shown in the photo. On 1300s, it returns to a fitting on the pump.