The coldest temperature, reported in 3 C steps, at which a chilled sample still moves when its test jar is tilted, measured under ASTM D97 or automated equivalents. In paraffinic mineral oils the limit is set by wax crystals locking into a network, and pour point depressant additives can push it down by 10 to 20 C. Pour point is a lab floor, not an operating limit: pumps and bearings need the oil well above it to circulate.
Pour point's -24 on that gear oil, so the outdoor conveyors need heaters before a January start.
Also heard as
- PP
Related terms
Viscosity
A fluid's resistance to flow, the lubricant property that sets how thick an oil film can build.
Viscosity index
Number showing how little an oil's viscosity changes with temperature; higher means flatter.
Channeling
Grease pushed aside by rolling elements so it sits in shoulders beside the track instead of churning.
PAO
Polyalphaolefin, the synthetic hydrocarbon base oil built from alpha-olefins and classed as Group IV.