Originally Posted by osprey877
Not sure if system will work
as well if the expansion tank is lower than the heat exchanger
Height of the expansion tank does not matter. Mine is midway between the engine
mount and the pressure cap. Same for the one I installed on my 1969 Dodge pickup. Both work
just fine. Air will find the highest point in the engine cooling
system, which is the pressure cap and will then be forced to the overflow (expansion) tank when pressure opens the cap. Fluid from the tank will be drawn back into the engine as it cools and resultant vacuum pulls it back. No air drawn back as long as the tube inside the tank remains submerged.