Concrete transport mixer will inevitably be damaged after use or long-term use, and the engine may also fail. Under what circumstances should the engine be overhauled? The details are as follows.

1.圆柱体的内径磨损，圆度偏差为0.04〜0.06 mm，圆柱度偏差为0.08〜0.12 mm（该差异通常由圆柱体的下半部和上半部测量）。对于多缸发动机，圆度和圆柱度之间的偏差取决于磨损大的气缸。

1. The inner diameter of the cylinder is worn, the roundness deviation is 0.04-0.06 mm, and the cylindricity deviation is 0.08-0.12 mm (the difference is usually measured by the lower and upper half of the cylinder). For multi cylinder engine, the deviation between roundness and cylindricity depends on the cylinder with large wear.

2.大大增加了机油的数量，降低了机油压力，并且排气管散发出深黑色和蓝色的烟雾。

2. Greatly increase the amount of oil, reduce the oil pressure, and the exhaust pipe emits dark black and blue smoke.

3.中科混凝土搅拌车的产量大幅下降。高马力约为输出的60％（不包括由于高海拔而导致的输出减小），而气缸压力小于标准压力的65％。

3. The output of Zhongke concrete mixer truck has decreased greatly. High horsepower is about 60% of rated output (excluding output reduction due to high altitude), while cylinder pressure is less than 65% of standard pressure.

4.曲轴磨损严重磨损后曲轴轴颈的圆度和圆柱度偏差超过大使用极限，或者圆度和锥度限制为0.10 mm。

4. After serious wear of crankshaft, the deviation of roundness and cylindricity of crankshaft journal exceeds the large service limit, or the roundness and taper are limited to 0.10 mm.

5.发动机启动或停止时，如果水温为50〜60℃，水温将无法平稳启动。

5. When the engine starts or stops, if the water temperature is 50 ~ 60 ℃, the water temperature will not start smoothly.

6.异常的发动机噪音或异常的运转，发动机在高温下运转时的气缸噪音（活塞爆震），主轴承或连杆轴承的剧烈振动或爆震噪音。

6. Abnormal engine noise or abnormal operation, cylinder noise (piston knock) when the engine is running at high temperature, violent vibration or knock noise of main bearing or connecting rod bearing.

以上是检修混凝土运输搅拌机发动机的条件，但是如果您再次了解这些条件，则会发现需要维修发动机。

These are the conditions for repairing the concrete mixer engine, but if you understand these conditions again, you will find that you need to repair the engine.