(1) Do not use diesel oil instead of diesel oil. The diesel oil has a lower viscosity than diesel oil and has a higher ignition temperature. If diesel oil is used instead of diesel, the diesel engine will not only be difficult to start, but will also cause increased wear of cylinders and pistons. (b) Do not use engine oil instead of gear oil The engine oil and gear oil have low viscosity and weak wear resistance and load resistance. If oil is used instead of gear oil, the transmission gear will not be well lubricated, causing serious damage to the transmission gear. (3) Do not use engine oil instead of brake oil Brake fluid has good solubility, no corrosion, and is less prone to sedimentation. The engine oil does not have the above characteristics. If it is used in place of brake fluid, it will easily produce sedimentation and will cause the brake system to produce rubber components. Expansion causes brake failure.