Diagnostics of Iveco Stralis 440ST Truck Tractor Unit Engine and Identification of the Cause of its Malfunction

The article concerns the case of the Iveco Stralis 440St truck tractor unit engine failure and the methodology of the technical expert applied to identify the cause of failure. The engine has repeatedly exhibited failuresleaking crankshaft spring - energised seal and consequent engine oil leak, which has been repeatedly repaired at a car service station. Repeated engine failures resulted in the disputes between a vehicle owner anda car service station, finally leading to an agreement on finding the cause by an invited technical expert. To determine the cause, a vehicle was on the car service station premises, where a technical expert was present and according to his instructions, diagnostic and subsequent disassembly works were done. The outcomes of the investigation proved serious damage to the engine piston unit.