The primary purpose of writing this book is to make available to the students, researchers and is prepared for case study projects. The current research deals with the reduction of wear and friction of automotive engine and gear components, and improving the performance of the IC engine by dispersing with multi-wall carbon nanotubes addition as additives in lubricating oil and gear oil.The performance test conducted on SI and CI engines with MWCNTs dispersed in lubricants shows an improvement in specific fuel consumption, brake thermal efficiency and mechanical efficiency at all loads and speeds when compared with that of base lubricant. The reduction in friction and improvement in performance is due to the rolling action of nanotubes between piston rings and cylinder. We shall be grateful, if the readers could communicate to us any suggestions and errors they discover.