Definition of Cavitation
Cavitation is the formation of vapor bubbles in the cooling system and their subsequent implosion. Vapor bubbles form in the coolant when the coolant temperature increases, coolant pressure drops or a combination of a decrease in pressure combines with an increase in temperature.
Process Responsible for Initializing Cavitation
The process that initiates cavitation is a sudden pressure drop and/or coolant temperature increase, which causes the coolant to change from a liquid to a vapor causing bubbles. As the bubbles contact the impeller, they burst. Liquid rushing in to occupy the space once occupied by the bubbles causes a high-pressure stream of liquid to contact the impeller, which causes erosion.
Erosion of the impeller caused by the removal of material through cavitation exposes the impeller to the chemical reactions in the coolant, thereby compromising the impeller through corrosion evident from pitting.
How to Reduce or Eliminate Cavitation
The easiest way to reduce or eliminate cavitation is to be sure you are using the proper coolant recommended by your vehicle’s manufacturer, your coolant doesn’t contain contaminants and sediment, and using the correct mixture ratio of coolant to distilled water.
- Be sure that your radiator cap is not leaking or faulty. If it is, or if in doubt, replace it.
- Repair even minor cooling system leaks.
- Replace any faulty cooling system components with quality products.
- Avoid any cooling system modifications.
Proper maintenance is key to reducing the chances of engine damage due to cavitation. Always check and maintain the proper coolant type and level in the radiator. Identify any obstructions, pinched or collapsed hoses or defective radiator cap, and replace them as necessary.