This paper analyzes the structural composition of the engine, combined with the relevant content of metal wear self-repair technology. Such as technical definition, working principle, technical characteristics, etc. Through the study of common fault performance of automobile engines, including failure to start, abnormal color of exhaust gas, abnormal noise etc. As well as the specific application of metal wear self-repair technology in the case of cylinder wear is not serious, cylinder and piston ring damage is serious, pull cylinder failure, etc. The purpose is to improve the engine repair efficiency and extend the service life of the car engine.