[Bob Bidonde]

Cylinder 4 does not get the benefit of pumped coolant flow, so it runs hotter. What compensates for the lack of pumped coolant flow about Cylinder 4 is the 3 coolant jackets that surround it. These jackets radiate enough heat from the coolant to keep Cylinder 4 at a successful operating temperature. However, the coolant jacket behind Cylinder 4 has a tendency to collect debris which degrades the radiation from the rear coolant jacket of the engine.


There is no coolant flow between the cylinders in the Model "A" engine, so the cylinders have hot spots where they connect. At Cylinders 3 & 4, the connecting cylinder walls run hot enough to eventually burnout the head gasket.