Cooling System Aeration

DIAGNOSIS AND TESTING - COOLING SYSTEM AERATION
Low coolant level in a cross flow radiator will equalize in both tanks with engine off. With engine at running and at operating temperature, the high pressure inlet tank runs full and the low pressure outlet tank drops. If this level drops below the top of the transmission oil cooler, aeration will occur drawing air into the water pump resulting in the following:
^ High reading shown on the temperature gauge.
^ Loss of coolant flow through the heater core.
^ Corrosion in the cooling system.
^ Transmission oil will become hotter.
^ Water pump seal may run dry, increasing the risk of premature seal failure.
^ Combustion gas leaks into the coolant can also cause the above problems.