In the world of industrial maintenance, there is a common scenario that plays out every day. A technician notices a motor bearing running a bit warm or sounding dry. They grab the nearest grease gun—loaded with whatever cartridge was on the shelf—and pump a few shots into the Zerk fitting.
The intention is good: lubrication extends life. But if the new grease has a different chemical thickener than the old grease, that technician has just turned the bearing into a failed chemistry experiment.
Grease incompatibility is one of the most misunderstood causes of bearing failure. At IVOR Bearings Inc., we see the forensic evidence of this error constantly. Here is why it happens and how to stop it.
It Is Not Just “Red Grease” vs. “Blue Grease”
The biggest myth in lubrication is that color indicates the type of grease. It does not. Manufacturers add dye for marketing purposes, not for chemical identification. You can have a Lithium Complex grease that is red, and a Polyurea grease that is also red.
Grease is composed of three parts: Oil (70-90%), Additives, and a Thickener (the “sponge” that holds the oil).
The problem arises when you mix incompatible thickeners.
What Happens When Thickeners Clash?
When two incompatible thickeners meet inside a bearing (for example, mixing a Lithium Complex grease with a Polyurea grease), a chemical reaction occurs that changes the physical structure of the lubricant.
This usually results in one of two disasters:
- Softening ( The “Soup” Effect): The mixture loses its ability to hold oil. The matrix collapses, and the oil runs out of the bearing, leaving the steel dry. You will see oil leaking past the seals, and the bearing will rapidly overheat and seize.
- Hardening (The “Concrete” Effect): The mixture reacts to form a hard, clay-like substance. This blocks the grease paths and prevents fresh lubricant from reaching the rolling elements. The bearing starves and burns up.
The Usual Suspects: Compatibility Chart
While you should always consult a formal compatibility chart, here are the general rules regarding the most common industrial greases:
- Lithium Complex: The most common general-purpose grease. It is generally incompatible with Polyurea, Calcium Complex, and Sodium greases.
- Polyurea: Common in electric motors (EMQ). It is often incompatible with almost everything else, including Lithium.
- Calcium Sulfonate: Gaining popularity for water resistance. It has fair compatibility with Lithium but poor compatibility with Polyurea.
The Golden Rule: Never assume compatibility. If you don’t know exactly what is inside the bearing, don’t guess.
How to Switch Greases Safely
If you decide to upgrade your plant to a higher-performance lubricant (for example, switching from standard Lithium to Calcium Sulfonate), you cannot simply start pumping the new grease in.
- Purge: If the bearing is purgeable, you must pump the new grease in while the machine is running until you see only the new color/texture expelling from the purge port. This ensures the old thickener is pushed out.
- Clean: For non-purgeable or critical bearings, the only safe way is to disassemble, clean the housing and bearing with solvent to remove all traces of the old grease, and repack manually.
- Label: Once switched, change the label on the lube point immediately. Use clear tags (e.g., “USE POLYUREA ONLY”) or color-coded washers on the grease fitting to match the grease gun.
Standardize to Survive
The best way to prevent mixing is to reduce the number of greases in your plant. Many facilities stock 10 different lubricants when they only need two or three.
IVOR Bearings Inc. acts as a technical partner for global operations. We help you consolidate your lubrication strategy, ensuring that the bearings we supply are pre-filled with the correct grease for your application, and helping you map out a safe maintenance plan.
Don’t let a simple refill shut down your line. Contact our technical team for a lubrication audit or to source the correct pre-lubricated bearings.
Contact us HERE, write at quotes@ivorbearings.com or call us at +1 305 769 9459.
In the world of industrial maintenance, there is a common scenario that plays out every day. A technician notices a motor bearing running a bit warm or sounding dry. They grab the nearest grease gun—loaded with whatever cartridge was on the shelf—and pump a few shots into the Zerk fitting.
The intention is good: lubrication extends life. But if the new grease has a different chemical thickener than the old grease, that technician has just turned the bearing into a failed chemistry experiment.
Grease incompatibility is one of the most misunderstood causes of bearing failure. At IVOR Bearings Inc., we see the forensic evidence of this error constantly. Here is why it happens and how to stop it.
It Is Not Just “Red Grease” vs. “Blue Grease”
The biggest myth in lubrication is that color indicates the type of grease. It does not. Manufacturers add dye for marketing purposes, not for chemical identification. You can have a Lithium Complex grease that is red, and a Polyurea grease that is also red.
Grease is composed of three parts: Oil (70-90%), Additives, and a Thickener (the “sponge” that holds the oil).
The problem arises when you mix incompatible thickeners.
What Happens When Thickeners Clash?
When two incompatible thickeners meet inside a bearing (for example, mixing a Lithium Complex grease with a Polyurea grease), a chemical reaction occurs that changes the physical structure of the lubricant.
This usually results in one of two disasters:
- Softening ( The “Soup” Effect): The mixture loses its ability to hold oil. The matrix collapses, and the oil runs out of the bearing, leaving the steel dry. You will see oil leaking past the seals, and the bearing will rapidly overheat and seize.
- Hardening (The “Concrete” Effect): The mixture reacts to form a hard, clay-like substance. This blocks the grease paths and prevents fresh lubricant from reaching the rolling elements. The bearing starves and burns up.
The Usual Suspects: Compatibility Chart
While you should always consult a formal compatibility chart, here are the general rules regarding the most common industrial greases:
- Lithium Complex: The most common general-purpose grease. It is generally incompatible with Polyurea, Calcium Complex, and Sodium greases.
- Polyurea: Common in electric motors (EMQ). It is often incompatible with almost everything else, including Lithium.
- Calcium Sulfonate: Gaining popularity for water resistance. It has fair compatibility with Lithium but poor compatibility with Polyurea.
The Golden Rule: Never assume compatibility. If you don’t know exactly what is inside the bearing, don’t guess.
How to Switch Greases Safely
If you decide to upgrade your plant to a higher-performance lubricant (for example, switching from standard Lithium to Calcium Sulfonate), you cannot simply start pumping the new grease in.
- Purge: If the bearing is purgeable, you must pump the new grease in while the machine is running until you see only the new color/texture expelling from the purge port. This ensures the old thickener is pushed out.
- Clean: For non-purgeable or critical bearings, the only safe way is to disassemble, clean the housing and bearing with solvent to remove all traces of the old grease, and repack manually.
- Label: Once switched, change the label on the lube point immediately. Use clear tags (e.g., “USE POLYUREA ONLY”) or color-coded washers on the grease fitting to match the grease gun.
Standardize to Survive
The best way to prevent mixing is to reduce the number of greases in your plant. Many facilities stock 10 different lubricants when they only need two or three.
IVOR Bearings Inc. acts as a technical partner for global operations. We help you consolidate your lubrication strategy, ensuring that the bearings we supply are pre-filled with the correct grease for your application, and helping you map out a safe maintenance plan.
Don’t let a simple refill shut down your line. Contact our technical team for a lubrication audit or to source the correct pre-lubricated bearings.
Contact us HERE, write at quotes@ivorbearings.com or call us at +1 305 769 9459.
