How to fill your Ford FE Expansion Tank

The stock location of the FE expansion tank is at the highest point of the cooling system.  As well as allowing room for the coolant to expand as it heat, its also helps to collect air at the top of the tank, improving cooling performance by removing air from the heads or top of the radiator.

So how much coolant should you aim for?

The tank has an internal stainless steel baffle plate, welded in at approximately the halfway height of the tank.  The baffle plate is open around the sides and has holes in it, one of which is visible through the radiator cap opening.

When filling the tank, it should be done with the engine cold.  The coolant should be level with the baffle plate, not higher.  This gives space for the coolant to expand.

If there is too much coolant in the tank, as it expands it will eventually overpressure the system and the 13psi cap supplied will vent the excess pressure though the outlet pipe.