The high temperature problem of CNC lathe bearings may be caused by many reasons. The solution can be to take the following measures according to the specific situation:

1. Lubricant selection: Make sure to use the appropriate lubricant and replace it according to the manufacturer's recommendations. The correct lubricant can effectively reduce friction and wear and help reduce bearing temperatures.

2. Lubrication system inspection: Check whether the lubrication system is operating normally, including whether the supply of lubricating oil is sufficient and whether the lubricating oil pump is working properly. Ensure that the lubrication system does not lead to insufficient lubrication due to blockage or failure.

3. Bearing cleaning: Make sure there are no impurities in the bearings and lubrication system, such as metal shavings, dust, etc. These impurities may cause increased bearing friction and generate excessive heat.

4. Bearing preload adjustment: Check whether the bearing preload is appropriate. If the preload force is too large or too small, it may cause the bearing to overheat. Make any necessary adjustments according to your lathe's manual or manufacturer's recommendations.

5. Bearing replacement: If the bearing has been damaged or severely worn, timely replacement of the bearing is an effective way to solve the problem. Choose high-quality, application-specific bearings.

6. Reduce the load: Check whether the load on the workpiece and tool is too large. It may be necessary to adjust the cutting parameters to reduce the cutting force, thereby reducing the load on the bearings.

7. Cooling system optimization: Ensure the normal operation of the cooling system. Consider increasing coolant flow, using a more efficient coolant, or using other cooling methods to improve cooling.

8. Check the bearing seat: Make sure the bearing seat is not damaged or deformed, which may cause the bearing to operate improperly.

9. Improve ventilation: Consider adding fans or ventilation equipment to the CNC lathe to help dissipate heat and reduce bearing high temperature problems.

10. Monitoring system: Use monitoring equipment such as temperature sensors to monitor the bearing temperature in real time, detect abnormalities in time and take measures.

When troubleshooting a problem, it's best to refer to the CNC lathe's manual or consult the manufacturer for more specific and professional advice.