[craggle]

Ian pointed me in the direction of this thread. Cheers

I did add a breather pipe from the top hose back to the header tank in my Chevy powered Dax. The Dax solution is a £75 thermostat housing with an additional pipe stuck in the side but I added my own pipe to the top hose. Any welding / fabrication shop should be able to do this.

The pipe can be seen in the attached photo. It is the pipe that goes from the top hose to the top of the header tank. It allows any air trapped in the engine to go to the highest point then vent back into the header tank.

Craig.