Pour point: Just as flashpoint when temperature is further lowered below cloud point of certain temperature, oil becomes semi-solid and losses its flow characteristics. This point is known as pour point. Pour point very much depends on presence of waxes in oil and the molecular structure of particular oil.
Significance:
1. The lubricating oils used in capillary feed system or wicking arrangement should have low pour point.
2. A high pour point leads to the solidification of lubricant that may cause jamming of the machines.
3. Pour point also gives an idea of the lowest temperature at which oil can be transferred by pouring.
4. Pour point determines suitably of the lubricant for low temperature installations which may be required to start and operate at sub-zero temperature.