We will talk about antifreeze here
Cylinder Liner Pitting caused by Cavatation
Pitting in cylinder liners is a direct result of cavitation erosion. This type of erosion develops from normal mechanical and chemical processes that take place during engine operation.
Cavitation of the cylinder wall begins when air bubbles remove the wall’s oxide film, which protects the metal from coming into contact with oxygen and corroding. Flexing of the cylinder wall (after fuel combustion) causes the cylinder liner to vibrate, and creates vapor bubbles in the coolant. These vapor bubbles form on the outside of the cylinder wall and explode inward, or implode, resulting in tiny pits on the cylinder wall’s protective oxide layer. When vapor bubbles continue to implode, enough energy is released to physically attack the cylinder wall and remove the oxide film. Corrosion and pitting then take place at a high rate.
If a pit breaks through the cylinder wall, coolant can leak into the cylinder and contaminate the lube oil. A sludge forms that can interfere in ring and bearing functions. Wear rates increase significantly and engine seizure may result
Thes small bubbles can be seen in the Killerglass tubes and proper precautions taken.
Cavitation damage is promoted by the following points:
- Insufficient anti-freeze in the coolant which could reduce the formation of vapor bubbles.
- The cooling system, e.g. the radiator cap, has a leak. This prevents pressure forming in the cooling system, promoting the formation of vapor bubbles.
- The cylinder liner in the crankcase has excessive clearance. Therefore,the vibrations caused by the contact alteration of the piston cannot be sufficiently absorbed.
- An incorrect coolant (acidic water, etc.) has been used
- The engine is operating in an insufficient temperature range. Therefore,the pressure level of the coolant is too low, promoting the formation of vapor bubbles. The piston does not reach its operating temperature, has excessive clearance and displays insufficient smoothness during contact alterations. An insufficient temperature range can be caused by the following:
- The thermostat or the thermo switch is defective.
- The viscous clutch of the fan wheel is defective, i.e. the fan wheel is driven permanently
- Always check the cooling system (radiator cap, hoses, clamps) for leaks.
- Ensure there are no air leaks in the cooling system.
- Ensure there is sufficient anti-freeze with corrosion protection. Replace Regularly
- Correctly bleed the cooling system when filling to ensure there are no trapped air pockets
- Make sure the cooling system is functioning correctly (thermostat, fan,thermo switch).
- Only use distilled water in the cooling system.
- Apply special protective coatings to the water jacket region of the sleeve outside surface E.g. chrome, copper, plasma, ceramic.