oil temp gauge gets hot engine stays cool

• 2022-09-02

Oil temp gauge gets hot engine stays cool: The large excavator is driven by the fan pump to adjust the speed of the fan motor. There is also an overflow device. Generally, the oil temperature is high. Check these places to solve the problem. 1. Too high oil temperature is harmful to the engine.

The temperature of the engine is too high, which means that the oil temperature and water temperature of the engine exceed 90 ℃.When the two temperatures are too high at the same time, it will affect the normal operation of the engine and bring certain harm to the engine: the gap will be reduced, and serious wear or "cylinder pulling" will be formed.The oil temperature mainly indicates the comparison between heat production and heat dissipation.The crankshaft and bearing generate heat due to friction, and the engine oil dissipates most of its heat. The balance between heat generation and heat dissipation (shown as stable oil temperature) is relative.When the heat generation exceeds the heat dissipation, the bearing bush temperature will rise, and the local temperature will reach the melting point of lead, and the lead in the bearing bush will melt and precipitate. After a large amount of lead is precipitated, the bearing surface of the bearing bush becomes smaller and uneven, which aggravates the wear. In serious cases, the local temperature can exceed the melting point of copper (1083 ℃), and the copper also begins to melt, which eventually leads to serious ablation of the crankshaft and bearing or the consequences of "bearing holding".

According to the test, when the oil temperature reaches 110 ℃, the oil film temperature in the bearing clearance can reach 150 ℃. If the oil film temperature is above 150 ℃, it is easy to break and form semi dry friction. As the crankshaft bearing is a copper lead alloy, if the reduction measures are not appropriate, the bearing temperature will be too high and lead will melt and precipitate, and the consequences are unimaginable.

The method of "load reduction and low rotation speed" is usually used to reduce the oil temperature. At this time, although the heat exchange time of the coolant at the high-temperature parts is long, the water flow speed slows down and the heat dissipation time is prolonged.At the same time, due to the reduction of load and rotation speed, the heat generated by the friction of various moving parts is also correspondingly reduced.Therefore, reducing the oil temperature can not only reduce the heat generated by the engine, but also indirectly reduce the heat absorbed by the coolant, thus slowing down the speed of water temperature rise.