A grease thickener formed from lithium 12-hydroxystearate combined with a short-chain complexing agent such as azelaic acid or a borate, lifting the dropping point above 260 C against roughly 190 to 200 C for simple lithium. Lithium complex greases are the most common multipurpose bearing grease in plants and fleets, with good water resistance, mechanical stability and pumpability. Many brands dye them red or blue, which is where shop talk of red grease comes from.
Default for motor bearings is lithium complex, NLGI 2, unless the tag on the fitting says different.
Color is a dye, not a spec. Red, blue and green greases can share the same chemistry, and two red greases can be incompatible.
Also heard as
- Li complex
- lithium complex soap
Related terms
Thickener
Solid structure in a grease, usually a metal soap or polyurea, that holds the base oil like a sponge.
Grease
Semi-solid lubricant made of oil held in a thickener sponge, usually with additives.
Dropping point
Temperature at which a heated grease turns fluid enough to drip from a test cup.
Grease compatibility
Whether two greases can be mixed without losing consistency, dropping point or stability.
Polyurea
Non-soap grease thickener with long high-temperature life, standard in sealed electric motor bearings.