Diagnosis and Testing: Aeration

If coolant level drops below a certain point, 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 (automatic transmission equipped vehicles).
• 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.