1, cradling inspection. Hand crank crankshaft, feel suddenly heavy, sometimes feel no compression force of each cylinder, remove the adjacent two cylinder fuel injector or spark plug, cut into thin circular pieces of paper, with grease stick In an injector or spark plug mounting hole, stick as tightly as possible, and then roll the car. You can also use a gas pipe to blow from another injector hole. If the disc is blown, the cylinder pad is in the cylinder. Burned between. ? 2, check from the exhaust pipe. If the cylinder pad burns through between the combustion chamber and the water jacket, the cooling water enters the cylinder, and a portion of the cooling water enters the exhaust manifold through the exhaust valve, thereby discharging water from the exhaust pipe. ? 3, oil inspection. Apply lubricant to the joint between the cylinder head and the cylinder block, that is, around the cylinder pad. If the engine is running, air bubbles will be emitted at the joint. In severe cases, a “click†sound will be emitted, indicating that the cylinder pad has burned through. ? 4, check out the oil ruler. If the cylinder pad burns through between the combustion chamber and the water jacket, the cooling water will enter the cylinder and part of it will leak into the oil pan. If the oil on the oil gauge contains water droplets, it indicates that the cylinder pad has burned through. ? 5, from the radiator inlet check. Fill the radiator with cooling water to keep the engine running at medium speed. Observe the radiator inlet. If bubbles continue to rise, after excluding the possibility of cylinder liner cracking, you can infer the cylinder pad in the combustion chamber and water jacket. Between burns, the more bubbles in the upper jaw, indicate that the cylinder pad burns through severely.