Abstract: In this study mechanical crankshaft failure for automobile is examined. This was done using data gathered by oral interviews and questionnaire administration on mechanical failure of crankshafts. The data collected were analysed using statistical methods based on probability. With this technique, probability of failure for each category of automobile considered-private, commercial cars and buses were evaluated. The results obtained showed that private cars enjoyed lowest failure rate at the initial stage while commercial buses had the highest failure rate. At the later periods all the categories considered had their failure rates very close to one another and at the same time they are insignificant (very small). At this point reliability gained its highest momentum. This showed that increased enlightenment campaign among the various stakeholders in automobile industries has gone a long way in improving reliability of mechanical crankshafts in automobile.