The cylinder pad is located between the cylinder head and the cylinder block, also known as the cylinder seat. Its function is to fill the tiny gap between the cylinder block and the cylinder head, ensure the good sealing of the joint surface, further ensure the sealing of the combustion chamber, and realize the prevention of air leakage between the cylinder and the water jacket. The following introduces the types of automobile cylinder pads and the fault symptoms after damage. Cylinder gasket type: 1. Metal asbestos cylinder gasket: asbestos sandwiched with iron wire or metal chips, covered with copper or steel skin. The thickness of the pad is 1.2~2mm. It has excellent elasticity and heat resistance, and can be used repeatedly, but its strength is poor, and its thickness and quality are uneven. 2. Solid metal cylinder gasket: This gasket punches convex strips with a certain height around the sealed cylinder hole, water hole and oil hole, and realizes sealing through elastic deformation of the convex strips. Mostly used to strengthen engines, mostly used in cars and racing cars. 3. Cylinder pad printed with asbestos and rubber adhesive: cylinder pad with woven steel wire mesh and central perforated steel plate as the skeleton and asbestos and rubber adhesive printed on both sides. Failure symptom after damage: 1. Air leakage between two adjacent cylinders: after the engine is started, there is insufficient power and black smoke, and the engine speed is obviously reduced. 2. Air leakage of cylinder head: there is light yellow foam at the air leakage, accompanied by water leakage and oil leakage. During the decomposition inspection, obvious carbon deposition can be seen on the corresponding cylinder head plane and its adjacent cylinder head bolt holes. 3. Gas-oil channel: oil bubbles obviously. 4. High-pressure gas enters the cooling water jacket: obvious bubbles rise in the water tank, accompanied by a large amount of hot gas released from the water tank mouth. With the increase of engine temperature, the hot air released from the water tank mouth gradually increases. 5. Oil leakage between the engine cylinder and the cooling water jacket or lubricating oil channel: yellow and black oil bubbles float on the cooling water in the oil tank, or there is obvious water in the oil in the oil pan. When these two kinds of air leaks are serious, the discharged gas will be stained with water or oil. The above is the introduction of the types of automobile cylinder pads and the fault symptoms after damage.