Mobil Polyrex™ EM Series

Mobil Polyrex™ EM electric motor bearing grease has earned an exceptional reputation for outstanding performance.

Our Mobil Polyrex™ EM grease is designed for electric motor bearings. Specially formulated to improve bearing performance and protection for long electric motor life, this grease is recommended by many major bearing and electric motor manufacturers for long-life lubrication of electric motor ball bearings and roller bearings.

Mobil Polyrex EM electric motor bearing grease provides:

  • Outstanding long-life, high-temperature lubrication
  • Increased durability compared to conventional greases
  • Protection against rust and corrosion
  • Low noise properties

  • Low bearing noise capability

  • Formulated with advanced polyuria thickener

  • Low oil release contributes to long-term lubrication

  • High-temperature performance

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Mobil Polyrex™ EM Series offers 2 lubricant grades

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Technical resources

Industrial grease lubricant application guide

Looking for a guide on which Mobil™ industrial grease best suits your needs? We have you covered.

English, pdf

Electric motor bearing lubrication guide

Keep your electric motors and your operation running smoothly by following best practices in grease lubrication.

English, pdf

Electric motor maintenance

Keep your electric motors in peak condition with some basic maintenance practices that are easy to do.

English, pdf

How to choose grease for electric motor bearings

Grease is frequently used to lubricate electric motor bearings because of its simplicity of application and unique characteristics. Read about what you should consider when choosing the proper grease.

English, article

All Mobil Polyrex™ EM resources


Features and Benefits

Mobil Polyrex EM and Mobil Polyrex EM 103 offer the following features and benefits:

FeaturesAdvantages and Potential Benefits
Outstanding grease lifeOutstanding long-life, high-temperature lubrication of ball and roller bearings, particularly in sealed-for-life applications
Advanced polyurea thickenerIncreased durability versus conventional polyurea greases when subjected to mechanical shear forces
Excellent corrosion resistanceMobil Polyrex EM and Mobil Polyrex EM 103 provide protection against rust and corrosion. Mobil Polyrex EM provides additional protection under mild salt-water wash conditions versus Polyrex EM 103
Low-noise propertiesMobil Polyrex EM is suitable for lubrication of ball bearings in many noise-sensitive applications 



Mobil Polyrex EM greases are recommended by many major bearing and electric motor manufacturers for long-life lubrication of electric motor ball and roller bearings.

Mobil Polyrex EM 103 is more specifically recommended for applications such as vertically mounted bearings, or very large motors where a stiffer grease consistency may be required by the OEM, and low noise properties are not required.

Mobil Polyrex EM greases have been shown to be compatible with a number of ExxonMobil lithium complex greases, as well as competitive electric motor mineral polyurea products, as determined by the methodology of ASTM D6185.  For specific questions about grease compatibility, contact your Mobil representative.

Key applications include: 

  • Electric motor bearings
  • Fin fan bearings
  • High-temperature pump bearings
  • Factory-filled, sealed-for-life ball bearings
  • Ball or roller bearings operating at high temperatures where low oil separation is required
  • Mobil Polyrex EM for ball or roller bearings operating in noise sensitive environments


Specifications and Approvals

Mobil Polyrex EM meets or exceeds the requirements of:Mobil Polyrex EMMobil Polyrex EM 103
DIN 51825: (2004-06)K2P-20 


Typical Properties

 Mobil Polyrex EMMobil Polyrex EM 103
NLGI Grade23
Base Oil Viscosity, ASTM D 445  
cSt @ 40°C115115
cSt @ 100°C12.212.2
Viscosity Index, ASTM D 22709595
Penetration, ASTM D217 worked, 60x, mm/10285250
Penetration Change after 100.000 strokes, ASTM D217, mm/104040
Dropping Point, ASTM D 2265, °C (°F)260270
Oil separation test, ASTM D 1742, %0.50.1
High Temperature Grease Life, ASTM D 3336, Hours @ 177°C750+750+
4-Ball Wear Scar, ASTM D 2266, @ 40kg, 1200 rpm, 75°C, 1 hr, mm0.410.6
Low Temperature Torque, ASTM D 1478, g-cm @ -29°C  
EMCOR Corrosion Performance, 10% Synthetic Sea Water ASTM D 6138 (Prepared As Per ASTM D 665B)0,1 (No Rust) 
Rust Protection, ASTM D 1743, Distilled WaterPassPass
Copper Corrosion Resistance, ASTM D 40481A1A
Water Washout, ASTM D 1264, %1.90.8


Health and Safety

Based on available information, this product is not expected to produce adverse effects on health when used for the intended application and when the recommendations provided in the Material Safety Data Sheet (MSDS) are followed. This product should not be used for purposes other than its intended use. If disposing of used product, take care to protect the environment.

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