The main reasons are the followings:

1.The nose is lack of the oil:

The lubricating oil have a function of lubrication and cooling inner the nose. If lack of oil, the cooling effect will reduce and the nose’s temperature will rise.

2.The effect of the lubricating oil is bad:

The oil cooler has a block.

3.The thermostatic valve has a fault:

If the thermostatic valve has a fault, it will result in the lubricating oil can not be cooled by the cooler and enter the nose after passing the thermostatic valve directly. Then the temperature of the nose rises.

4.The oil stop valve has a fault:

If the oil stop valve can not start timely during the operation, this will result in the lubricating oil can not form a recycle inner the air compressor and can not have a cooling effect on the nose.