Abstract: This paper presents an investigation report of different components failure which affect the performance of an automobile engine. The premature breakage of a four cylinder diesel engine block, crankshaft, camshaft, crankshaft bearing, camshaft bush, engine oil pump was reported. It is found that the failure of each component having the same reason for its failure as reported from different place. Thus it affected the performance of the vehicle and it is very expensive for the customer to replace the damaged parts for several times. In this paper, we presented detailed analysis of the causes for the failure along with preventive suggestion to maintain the engine for better performance.