Q: What is "Pour Point", why and when is it important?
A: Pour Point is defined as the lowest temperature at which a liquid is still fluid enough to pour, therefore pour point serves as a valuable tool in determining cold temperature performance. The lower the pour point the better the cold temperature fluidity of a lubricant.
You may be wondering what influences the pour point to begin with. Well the pour point is determined by the amount of wax present in the products base oil. At low temperatures these waxes start to crystallize and then solidify to a point where the lubricant can no longer move. The more refined the base oil the less wax is present and the lower the pour point.
Previously we discussed using the correct viscosity and compensating for temperature. Lets say you did the exercise and adjusted the viscosity to suit the ambient temperature. However it does not end there. If your operating temperature is below 0°C you would need to dig a bit deeper. Let's say for example your ambient temperatures are -10°C and you have compensated for the low temperature by selecting an ISO 32 grade oil instead of an ISO 150. However the Product Data Sheet (PDS) shows a pour point temperature of -5°C. Given this scenario you would have to discard the use of the new ISO 32 oil and find another lubricants with a lower pour point.