[Kurt in NJ]

The cooling system of the A is pump assisted thermosyphen, thermosyphen action starts working when coolant is over 180--- watch a pot of water before it boils, the water gets active and flow can be seen a little before boiling, perhaps it not that #4 is too hot, but other areas are too cold
I found with my car that the temperature was just a few degrees different, and the hotter/cooler places moved some depending on idling,driving slow-fast, heat soak
I have a 160 degree thermostat, but it is old in hose bi- metal type with butterfly valve