一台东方红-75拖拉机,起动后一切正常。待发动机温度升高到70℃以上时,排气管开始冒白烟,并带有“啪啪”的响声,用手或白纸对准排气管上方测试时,发现有细微的水珠。经分析判断是有水进入气缸内而引起。当拆下气缸盖检查时,发现一缸进气门座圈处有一条约10毫米长的裂纹。当拖拉机起动时,温度较低,裂纹缝隙小,不易渗水;当发动机温度升高到70℃以上时, An Oriental Red -75 tractor, everything started normal. Until the engine temperature rises above 70 ℃, the exhaust pipe began to take white smoke, and with the “snap snap” sound, hand or white paper at the top of the exhaust pipe test, found that there is fine water Beads The analysis to determine that there is water into the cylinder caused. When the cylinder head inspection was removed, a crack of about 10 mm was found at the cylinder intake valve seat. When the tractor starts, the temperature is low, the crack gap is small, not easy to seep water; when the engine temperature rises above 70 ℃,