Grease is one of the most misunderstood lubricants in industrial and automotive maintenance. Many maintenance technicians default to NLGI 2 for everything — a reasonable starting point, but not always correct. Choosing the wrong grease consistency can lead to bearing failures, pump blockages, or grease purging from housings in ways that reduce lubrication effectiveness.
What Is NLGI Consistency Grade?
NLGI stands for National Lubricating Grease Institute, and the consistency grade is a standardized measure of how stiff or fluid a grease is. The scale runs from NLGI 000 (very fluid, almost like an oil) to NLGI 6 (very stiff, brick-like). The test used is the cone penetration test — a standardized cone is dropped into the grease and the depth of penetration in tenths of a millimeter is measured. Higher penetration (softer grease) = lower NLGI grade.
NLGI 0 and 00: Semi-Fluid Greases
NLGI 00 and 0 greases are nearly fluid at room temperature and flow under gravity. They are used in centralized lubrication systems where fluid flow through lines and fittings is required, gear cases where a fluid lubricant is needed but an oil circulation system is not practical, and industrial gearboxes with slow rotation where fluid grease provides better coverage.
NLGI 1: Soft Grease for Cold and Low-Speed Applications
NLGI 1 is softer than standard bearing grease and is used for: low-temperature applications where stiffer grease would not flow adequately to lubricate bearing surfaces, large slow-speed bearings where good coverage requires the grease to flow across the bearing surface, and some centralized lubrication systems where NLGI 2 proves too stiff to pump reliably.
NLGI 2: The Universal Standard
NLGI 2 is the most widely used grease consistency in industrial, automotive, and marine applications. It strikes the balance between stiffness (stays in place in bearing housings) and softness (can be pumped through grease guns and centralized systems, and penetrates bearing cages adequately). Ball bearings, roller bearings, automotive wheel bearings, electric motor bearings, and most general-purpose applications use NLGI 2.
NLGI 3: For High-Speed, High-Temperature, and Sealed Applications
NLGI 3 is stiffer than standard bearing grease and is preferred for: high-speed bearings where fluid grease would be centrifuged out or churned excessively, sealed-for-life bearings where the grease must remain in place without replenishment, high-temperature applications (kiln bearings, oven conveyors) where the grease must resist softening, and electric motors in hot environments where grease leakage onto windings must be prevented.
Base Oil Type in Grease Also Matters
Beyond NLGI grade, the base oil in the grease matters for temperature range and compatibility. Lithium complex greases provide high temperature performance (dropping point above 250°C) and are widely used. Calcium sulphonate greases offer excellent water resistance and are preferred in marine and wet environments. Polyurea greases are used in sealed-for-life bearings. PTFE (Teflon) greases are food grade compatible and used in light-load, clean environments.
📞 CONTACT & CTA
Lukeron supplies industrial and marine greases in NLGI 1, 2, and 3 grades. Contact us: +91 73832 79438 | info@lukeronlubricants.com
