VALVE GP-PILOT 9T8693 - Caterpillar

3406, 3408, 3412 Engines In All ApplicationsDescription of Change: New cylinder liners are used in the above model engines. The new liners have more clearance between the outside diameter of the liner and the bore in the cylinder block at the bottom end of the liner. The increased clearance will be of assistance in the reduction of pitting (small holes in the metal surface) of the cylinder block and liners when correct procedures are followed for cooling system maintenance. To keep pitting at a minimum, you must use the cooling system maintenance recommendations in the article "New Recommendations for Cooling System Maintenance to Prevent Engine Damage".Adaptable To: All 3406, 3408 and 3412 Engines. The new 7N943 Cylinder Liner is a direct replacement for the former 4N1627 Cylinder Liner, which is canceled. This new cylinder liner is in effect on engines with the serial numbers shown in the chart.