See if the trademark logo is complete. The quality of the outer packaging of the original auto parts is good. The box has clear writing and clear color. The box and bag should be marked with the product name, specification and model, quantity, registered trademark, factory name and telephone number. Some manufacturers also put their own marks on the accessories. Some important components such as generators, distributors, fuel injection pumps, etc., are also equipped with instructions for use. Certificate of compliance and inspector. To guide users to use maintenance properly. Care should be taken when purchasing, in case of buying fake and shoddy products. Look at the geometric size with or without deformation Some automotive parts are subject to manufacturing, transportation, improper storage, and are prone to deformation. When inspecting, roll the shaft part along the glass plate one turn. Look at the contact between the parts and the glass plate to see if there is any light leakage to judge whether it is bent. When purchasing the clutch disc or the friction plate, the steel piece and the friction plate can be lifted in front of the eyes to observe whether it is warped. When purchasing the oil seal, the oil seal end face with the skeleton should be rounded, can be fitted with the flat glass without deflection, and the outer edge of the non-frame oil seal should be straight. Hold it with your hand and deform it. After you release it, you should be able to return to its original shape. When purchasing various types of gaskets, you should also check the geometry and shape. See if the joint parts are flat. During the handling and storage of the automobile parts, due to vibration and bumps, burrs are often generated at the joints. Indentations, breakage or cracks affect the use of parts. Pay attention to check when purchasing. Look at the surface of the part for rust. Qualified parts have a certain degree of precision and a bright finish. The more important the parts, the higher the accuracy. The stricter the anti-rust and anti-corrosion of packaging. Pay attention to check when purchasing. If the parts are found to have rust spots, mold spots or rubber pieces are cracked. Losing flexibility. Or the surface of the journal has obvious turning pattern. Should be exchanged.