CYLINDER BLOCK ASSEMBLY 8S8068 - Caterpillar

Machine Engines:
3304 (S/N: 07Z; 09Z; 12Z)
3306 (S/N: 08Z; 10Z; 13Z; 6NC)
Description of Change: Severe engine overheating can cause the fuel injector tip to become loose. The tip could become loose and the tip could drop off the end of the barrel. This could cause extensive damage to the piston, the liner, the valve and the turbocharger.Adaptable To: This procedure is adaptable to all machine engines that are listed above. The following procedure should be considered as the criteria for dealing with engine overheating.A MINOR engine overheating could occur if the operator observes that the machine is slowly overheating. This would normally show that the needle of the gauge would slowly approach the midpoint of the red zone. The operator should remove the load. The operator should then drop the engine speed to 1200 rpm. This observation would be considered as MINOR overheating if the gauge dropped back into the normal zone.A SEVERE engine overheating could occur if the operator never noticed the gauge and the needle was at the high limit of the red zone. The operator does not know the amount of time that the needle was at the high limit of the red zone. The operator should reduce the load. The operator should then reduce the engine speed. The metal should start to contract. A SEVERE engine overheating occurred if the operator hears a crackling sound of overheated metal.If there was a SEVERE engine overheating, replace all the fuel nozzles.If the overheating was of a lesser magnitude, then check the injector of the rear cylinder by removing the injector and checking the carbon dam for melting. Also check for any discoloration of paint on the nozzle body. If either condition is present, replace all nozzles in the set. If no melting of the carbon dam has taken place and no discoloration of the paint on the body has occurred, then install new carbon dams and reuse the injectors. If a nozzle tip is lost on any cylinder of the engine, then all injectors need to be replaced.Reference: Refer to Special Publication, SEBD0639, "Analyzing Fuel Nozzle and Fuel Line Failures".