Sealant is a new type of sealing material that appears in the maintenance of modern automobile engines. The emergence and development of automobile sealants provide good conditions for improving sealing technology and solving the "three leaks" of engines. There are many types of sealant, it can be applied to different parts of the car. Automobile engines usually use non-adhesive (commonly known as liquid gasket) sealant. It is a viscous liquid substance with a high molecular compound as a matrix. After coating, it forms a uniform, stable, continuous adhesive thin layer or peelable film on the joining surface of parts, and can fully fill the depressions and Go in the gap. The sealant can be used alone or in combination with their gaskets in the engine valve chamber cover, oil sump, valve lifter chamber cover, etc., or under the last bearing cover of the crankshaft, as well as the oil hole plug and oil plug Wait. When repairing car engines, the "three leaks" (water leaks, oil leaks, and air leaks) are the most headaches for maintenance personnel. The "three leaks" seem to be ordinary and worth mentioning, but it directly affects the normal use of the car and the cleanliness of the appearance of the car engine. Whether the "three leaks" in important parts of the engine can be strictly controlled is an important issue that maintenance personnel must consider. Therefore, the quality of engine seals and their correct selection directly affect the quality of engine sealing performance.