Tier 4 Final engines produce massive peak cylinder pressures to burn clean and meet emissions. This extreme combustion force is causing a violent, hidden failure mode inside the engine block: coolant cavitation eroding the cylinder liners.
When the fuel ignites, the shock wave causes the cast-iron cylinder liner to ring and vibrate microscopically. On the coolant side of the liner, this vibration violently pulls the coolant away from the metal, creating microscopic vacuum bubbles. A fraction of a second later, the coolant crashes back against the liner wall, collapsing the bubbles with an extreme, localized water-hammer effect.
Over thousands of hours, this continuous microscopic pounding literally beats the cast iron away. The liner develops a porous, spongy texture. Eventually, the cavitation eats a pinhole completely through the liner wall. Coolant enters the combustion chamber, hydro-locking the cylinder and bending the connecting rod. The only defense is the Supplemental Coolant Additive (SCA) package. SCAs coat the coolant side of the liners with a microscopic, self-sacrificing layer of silicate. The cavitation beats away the silicate instead of the iron. If the fleet manager ignores the SCA concentration-or mixes incompatible OAT (Organic Acid Technology) coolant with traditional green coolant-the protective layer fails, and the engine eats itself from the inside out.
