How to Choose the Right Grease: NLGI Grade, Thickener, Base Oil & Additives
By on Aug 24 2026
Choosing the right grease takes more than matching a brand name or grabbing the same NLGI grade you used last time.
The right grease depends on the equipment, operating temperature, load, speed, water exposure, base oil viscosity, thickener, additives, and any specifications required by the equipment manufacturer.
Understanding those differences can help you narrow the options and find a grease that better fits the application.
If you already know some of your requirements, Petroleum Service Company’s Grease Selector Tool can help you get started.
Find the Right Grease with the PSC Grease Selector
PSC carries greases for automotive, aviation, heavy-duty truck, industrial, and off-road equipment applications. The Grease Selector lets you narrow that selection using the properties that matter for your equipment.
You can filter products by:
- Industry
- NLGI grade
- Thickener
- Base oil
- Base oil ISO viscosity
- Texture
- Color
- Food Grade NSF H1 registration
- Wheel bearing approval
- Moly
- Graphite
- PTFE
Ready to narrow your options? Use the PSC Grease Selector to filter products based on the properties your application requires.
Once you find potential matches, review the Product Data Sheet and your equipment manufacturer’s lubrication requirements before making a final selection.
What Is Lubricating Grease?
Grease is a semi-solid lubricant typically made from three main components:
Base oil: Provides much of the lubricating film between moving surfaces.
Thickener: Holds the base oil in place and gives the grease its consistency.
Additives: Provide additional properties such as wear protection, corrosion resistance, extreme-pressure performance, oxidation resistance, water resistance, or other application-specific benefits.
One reason grease is used instead of lubricating oil is its ability to remain where it is applied. That can make it useful for bearings, chassis points, enclosed components, equipment exposed to contaminants, and applications where leakage or frequent oil circulation would be impractical.
But not all grease behaves the same way.
What NLGI Grease Grade Do You Need?
One of the first numbers you will encounter when shopping for grease is its NLGI grade.
NLGI grade describes the consistency of the grease, or how soft or firm it is. It does not indicate the quality of the grease, and it should not be confused with the viscosity of the base oil.
The NLGI scale ranges from very fluid greases to extremely firm products.
Common NLGI Grease Grades
NLGI 000: Very fluid or semifluid grease. Often used in certain enclosed gear systems and centralized lubrication applications.
NLGI 00: Semifluid grease commonly used where good pumpability and flow are important.
NLGI 0: Soft grease that may be used in centralized lubrication systems and applications requiring easier movement through lines.
NLGI 1: Softer than the commonly used NLGI 2 grade and useful in applications where pumpability or lower-temperature performance is important.
NLGI 2: One of the most commonly encountered grease consistencies and widely used in bearings, chassis points, industrial equipment, and general-purpose applications.
Higher NLGI grades become progressively firmer and are used in more specialized applications.
Is NLGI Grade the Same as Grease Viscosity?
No. NLGI grade describes the consistency of the finished grease.
Base oil viscosity describes the resistance to flow of the lubricating oil contained within that grease.
Two products can both be NLGI 2 greases while using very different base oil viscosities and serving very different applications.
That is why NLGI grade should be treated as one part of the selection process rather than the entire answer.
Choosing the Right Base Oil and Viscosity
The base oil does much of the lubricating work inside a grease. Its viscosity helps determine the thickness of the lubricating film between moving surfaces.
As a general principle, slower-moving equipment operating under heavier loads may require a heavier base oil, while faster-moving components may require a lighter oil.
Temperature also matters. Lubricant becomes thicker as temperatures fall and thinner as temperatures rise. The appropriate viscosity needs to maintain enough lubricating film without creating unnecessary resistance or interfering with equipment operation.
The correct choice should ultimately come from the equipment manufacturer’s recommendations and the conditions under which the equipment operates.
Which Grease Thickener Should You Choose?
The thickener gives grease its structure and affects characteristics such as water resistance, temperature capability, mechanical stability, and pumpability.
Lithium and Lithium Complex Grease
Lithium greases are widely used across automotive and industrial applications.
Lithium complex greases generally provide higher temperature capability than conventional lithium greases and are commonly found in multipurpose and heavy-duty formulations.
Calcium and Calcium Sulfonate Complex Grease
Calcium-based greases are often selected where water resistance is important, like FUCHS RENOLIT LGM 2.
Calcium sulfonate complex formulations can combine strong water resistance with corrosion protection and load-carrying performance.
Polyurea Grease
Polyurea grease is frequently associated with electric motor bearings and other long-life bearing applications.
Aluminum Complex Grease
Aluminum complex thickeners can provide good water resistance and are also used in some food-grade and industrial grease formulations.
Other thickener systems are available for more specialized operating environments. The important takeaway is that the thickener is not simply an ingredient on the label. It can significantly affect where and how the grease performs.
What Do Moly, Graphite, and PTFE Do in Grease?
Grease additives can provide additional performance beyond the base oil and thickener.
Moly Grease
Molybdenum disulfide, commonly called moly, is a solid lubricant often added to grease used in heavily loaded or shock-loaded applications.
Moly grease is commonly associated with construction equipment, pins, bushings, chassis points, and other applications where sliding contact and heavy loads may occur.
However, moly is not automatically the best additive for every bearing or lubrication point. Always verify the equipment requirements.
Graphite Grease
Graphite is another solid lubricant used in certain heavy-load, high-temperature, or severe-service applications.
PTFE Grease
PTFE can be used to reduce friction and provide additional lubricating properties in specialty grease formulations.
These additives should not be confused with the grease thickener. For example, a lithium grease may contain moly, while another lithium grease may not.
How to Choose Grease by Application
Instead of asking, “What is the best grease?” it is usually more useful to ask, “What grease is right for this application?”
Grease for Bearings
Bearing grease selection depends on factors such as bearing type, speed, load, operating temperature, base oil viscosity, relubrication interval, and exposure to water or contamination.
High-speed electric motor bearings may require something very different from slow-moving, heavily loaded industrial bearings.
Wheel Bearing Grease
Wheel bearing applications can involve heat, load, water exposure, and high rotational speeds.
Look for products specifically recommended or approved for wheel bearing service rather than assuming any multipurpose grease will work.
The PSC Grease Selector includes a Wheel Bearing Approved filter to help narrow applicable products.
Grease for Heavy Equipment
Construction and off-road equipment can place grease under heavy loads, shock loading, dirt, water, and frequent movement.
These applications may require extreme-pressure properties, water resistance, or solid additives such as moly depending on the lubrication point.
Grease for Electric Motors
Electric motor bearings often operate at relatively high speeds and may require carefully selected base oil viscosity, thickener type, and consistency.
More grease is not necessarily better in an electric motor bearing. Always follow the motor or bearing manufacturer’s lubrication instructions.
Food-Grade Grease
Equipment used in food processing facilities may require lubricants registered for specific food-industry applications.
NSF H1 grease is intended for applications where incidental food contact may occur.
If food-grade lubrication is required, the PSC Grease Selector allows you to filter for Food Grade NSF H1 products.
Automotive and Chassis Grease
Automotive grease may be used for chassis points, steering components, suspension components, universal joints, and certain bearing applications.
The correct grease will depend on the vehicle and lubrication point, so check the manufacturer recommendation before selecting a product.
Aviation Grease
Aircraft grease requirements can be highly application-specific.
Do not substitute a grease based solely on consistency or appearance. Confirm the required specification and manufacturer approval for the aircraft or component before use.
Can You Mix Different Types of Grease?
Greases should not automatically be assumed to be compatible.
Different thickener systems, base oils, and additives can react poorly when mixed. Incompatible greases can soften, harden, separate, lose mechanical stability, or otherwise perform differently than intended.
If you are changing from one grease to another, check grease compatibility information from the lubricant manufacturers and follow the equipment manufacturer’s recommendations.
When compatibility is uncertain, removing as much of the previous grease as practical before introducing the new product is generally preferable to blindly mixing the two.
Important: The PSC Grease Selector is a product-selection tool, not a grease compatibility calculator. Use manufacturer compatibility data when determining whether two specific products can safely be mixed.
What Grease Should I Use?
Start with the equipment manufacturer’s requirements, then consider the conditions in which the grease will operate.
- Application: What component are you lubricating?
- NLGI grade: How soft or firm does the grease need to be?
- Base oil viscosity: What load, speed, and temperature will the lubricant experience?
- Thickener: Does the application require specific water resistance, temperature capability, or pumpability?
- Temperature: What are the minimum and maximum operating temperatures?
- Load: Will the equipment experience heavy or shock loads?
- Water exposure: Will the grease encounter moisture, washdown, or outdoor conditions?
- Additives: Does the application call for moly, graphite, PTFE, or another performance additive?
- Specifications and approvals: Does the equipment require NSF H1, wheel bearing approval, an OEM specification, or another standard?
Find Grease for Your Application with PSC
PSC carries greases for automotive, aviation, industrial, heavy-duty truck, off-road equipment, food processing, bearings, centralized lubrication systems, and other applications.
Instead of searching through every grease individually, use the PSC Grease Selector to narrow the catalog by the properties your application actually requires.
Filter by NLGI grade, thickener, base oil, viscosity, industry, additives, and specifications, then review the matching products and their technical data before making your selection.
