Basic Knowledge About Engine

1. What are the causes of cylinder cooling water pressure fluctuations?

A: Cylinder cooling water pressure fluctuations are usually due to the presence of gas in the system. The causes may include:

1) Insufficient aeration during system filling and machine operation, leading to air (or water vapor) accumulation in the pipes or cooling space.

2) Closure of the vent valve connecting the expansion tank to the cylinder head cooling water outlet or the expansion tank.

3) Gas combustion entering the cooling water through cracks in the cylinder or cylinder head.

4) Blockage in the cooling water pipes, a damaged or nearly closed regulating valve, insufficient cooling water in the system, and overheating of the cooling water, resulting in gas production.

5) Improper sealing at the cylinder lubrication oil pipe joint, allowing gas combustion to leak into the cooling water space.

Gas (vapor) in the cooling water space not only causes cooling water pressure fluctuations but also significantly reduces the cooling effect of the cylinder block and cylinder head in the affected area, potentially causing localized overheating and damage. Therefore, if gas is found, it should be released as soon as possible.

2. What are the causes of excessively high cylinder coolant temperature?

A: The causes of excessively high coolant temperature in individual cylinders may include:

1) Overloading or severe afterburning in that cylinder.

2) Piston overheating or cylinder seizure.

3) The coolant shut-off valve for that cylinder is closed or damaged, causing a lack of coolant.

4) Blockage in the coolant pipe leading to that cylinder.

3. What measures should be taken when cylinder overheating is caused by insufficient or interrupted coolant or cylinder oil supply?

A: When cylinder overheating is found to be caused by insufficient or interrupted coolant or cylinder oil supply, the following measures should be taken:

1) Immediately switch to light diesel oil, reduce vehicle speed, check the temperature of each cylinder, cut off fuel supply to the overheating cylinder, and fill the cylinder with maximum fuel.

2) Check the coolant level in that cylinder. If the coolant level is insufficient or completely interrupted, the coolant level should be increased slowly unless the overheating reaches a dangerous level.

3) If the coolant supply is normal, but cylinder overheating is caused by insufficient or interrupted cylinder oil supply, reduce speed and increase cylinder oil supply. If the situation is not serious, slowly restore the oil supply to normal.

At this time, pay attention to:

①. The piston coolant supply should continue as normal to remove heat from the piston as much as possible and accelerate cylinder cooling.

②. Once the cylinder overheating has subsided, the oil pump for that cylinder can be resumed, and the vehicle speed can be gradually increased. Observe the engine carefully for a period of time.