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Grease NLGI grades explained

Grease labels show an NLGI grade that describes consistency, from soft and pumpable to hard. Here’s how to read those numbers.

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Grease is oil held in a thickener so it stays where you put it. The National Lubricating Grease Institute (NLGI) consistency grade is a standard way to describe how soft or firm a grease is at a test temperature. It does not by itself tell you the thickener type, the base oil viscosity or the load rating, so it is only one part of choosing a grease.

The NLGI scale, in plain terms

NLGI grades run from 000 (very soft, almost fluid) up through 0, 1, 2, 3 and on to 6 (very hard). A higher grade number means a firmer grease in the standard penetration test.

  • 000, 00, 0: soft greases, often used in centralized systems or gearboxes that call for a semi-fluid grease.
  • 1: soft, easier to pump in cold weather than a #2 in many applications.
  • 2: the most common multi-purpose grade for automotive and light equipment fittings.
  • 3 and higher: firmer greases for applications that specify them.

If a manual says “NLGI #2 GC-LB” or similar, both the consistency grade and the performance classification matter. GC-LB is a common automotive chassis and wheel-bearing performance classification; your manual says whether you need it.

Matching grease to the job

  1. Read the equipment manual for NLGI grade, thickener preferences and any performance specs.
  2. Use the right grease gun and clean fittings so dirt isn’t pushed into the bearing.
  3. Pump until you see fresh grease purge the old grease at joints that are designed for that, and wipe the excess.
  4. Don’t mix chemistries carelessly. If you change thickener types, purge as thoroughly as the manual allows, or ask a technician.

For chassis and trailer work, see the towing season checklist. For farm and construction fittings under heavy shock loads, look at the products below and confirm with the lookup guide.

Frequently asked questions

What NLGI grade do most cars use?

Many automotive chassis and wheel-bearing applications specify NLGI #2, often with a GC-LB performance classification. Always check your manual.

Does a higher NLGI number mean better grease?

No. It only means a firmer consistency in the standard test. The right grade is the one your equipment manufacturer specifies.

Can I mix two different greases?

Mixing thickeners can soften or harden a grease and reduce performance. When changing types, purge old grease as thoroughly as the application allows, and follow the manual.

AMSOIL greases and NLGI grades

  • AMSOIL Synthetic Multi-Purpose Grease (NLGI #2). AMSOIL says it “meets the performance requirements of the NLGI GC-LB and HPM core specifications,” offers “outstanding low-temperature pumpability,” and is “recommended in heavy- and light-duty applications found in manufacturing facilities, automobiles, trailers and landscaping, agricultural and powersports equipment.”
  • AMSOIL NLGI #2 Synthetic Polymeric Off-Road Grease. AMSOIL says it delivers “outstanding extreme-pressure protection,” “stays in place to help seal out contaminants” and “resists impact from shock loads,” and lists it for heavy equipment such as dozers, tractors, loaders and excavators.
  • AMSOIL Synthetic Water-Resistant Grease. AMSOIL says it is “specially formulated for wet-duty performance” with “excellent water-washout resistance,” and recommends it for applications exposed to water, mud, snow or ice, including boat trailers.

Product wording above is quoted or summarized from amsoil.com. Read each product’s label and data sheet for directions.

Confirm the grade and specs with your manual and AMSOIL’s official lookup guide.