Mobil Polyrex EM 103 Grease (NLGI 3)
Mobil Polyrex EM 103 Grease (NLGI 3)
SKU:149045
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Mobil Polyrex™ Series — Electric Motor Bearing Grease
Mobil Polyrexâ„¢ EM 103
Electric Motor Bearing Grease | NLGI 3 | Polyurea Thickener | Vertical Mount & Large Motors
Stiffer Consistency — Engineered for Vertical Mounts & Large Motors
Mobil Polyrex EM 103 is the NLGI 3 grade in the Polyrex EM Series, providing the same super-premium polyurea formulation as Polyrex EM in a firmer consistency specifically recommended for vertically mounted bearings, or very large motors where OEM specifications call for a stiffer grease.
The Polyrex EM Series was specifically engineered to solve the failure modes that conventional greases suffer in electric motor applications — and EM 103's stiffer consistency was developed for the specific problem of grease slumping and migration in vertical bearing housings, where a softer grade would run out under gravity and leave the bearing under-lubricated. For South African manufacturing and processing facilities running large or vertically mounted motors, Polyrex EM 103 is the correct choice where bearing fill retention and long-term reliability are the priority.
Product Overview
Mobil Polyrex™ EM 103 is a super-premium electric motor bearing grease formulated with an advanced polyurea thickener and proprietary manufacturing techniques — delivering improved bearing performance and protection for long electric motor life. The NLGI 3 consistency is specifically recommended for applications such as vertically mounted bearings, or very large motors where a stiffer grease consistency may be required by the OEM.
The advanced polyurea thickener provides increased durability versus conventional polyurea greases when subjected to mechanical shear forces — maintaining grease structure and bearing protection over the full service interval. Mobil Polyrex EM 103 also delivers excellent corrosion resistance and superior oil separation and water washout resistance compared to standard Polyrex EM, making it particularly well suited to large-frame motors operating in demanding industrial environments.
Mobil Polyrex EM 103 is compatible with a number of ExxonMobil lithium complex greases and competitive electric motor mineral polyurea products, as determined by ASTM D6185 methodology. Available in 18kg pail and 180kg drum from Orbit Industrial — distributing Mobil lubricants across the Western Cape, Northern Cape and Garden Route.
Why NLGI 3 Matters for Vertical Mounts & Large Motors
The case for a stiffer NLGI 3 grease is stronger in vertical bearing and large motor applications than in standard horizontal motor installations — because the consequences of using the wrong consistency are uniquely costly:
Grease Migration — The Primary Failure Mode
In vertically mounted bearings, softer NLGI 2 greases can slump and migrate downward under gravity over time, leaving the upper bearing race under-lubricated. The stiffer NLGI 3 consistency of Polyrex EM 103 resists this migration and maintains correct bearing fill throughout the service interval.
Superior Oil Separation Resistance
Oil separation of just 0.1 mass% — meaningfully lower than standard Polyrex EM's 0.5% — reducing oil bleed and maintaining consistent lubrication in large-frame and high-temperature motor applications.
Excellent Water Washout Resistance
Water washout loss of just 0.8 wt% provides strong resistance to grease loss in humid or wash-down industrial environments where bearing housings are exposed to moisture.
OEM Compliance for Large Motors
Many large-frame electric motor OEMs specify a firmer NLGI 3 grease for the higher loads and bearing geometries common in large industrial drive motors — Polyrex EM 103 meets this requirement directly.
Full Performance Benefits
Stiffer Consistency for Demanding Mounts
The NLGI 3 grade resists slumping and migration in vertically mounted bearings, holding its structure where a softer NLGI 2 grease would run out of the bearing housing under gravity.
Advanced Polyurea Thickener
Increased durability versus conventional polyurea greases when subjected to mechanical shear forces — maintaining grease structure and bearing protection over the full service interval.
Outstanding Grease Life
750+ hours of lubrication life at 177°C allows significantly extended re-lubrication intervals — reducing maintenance frequency and labour cost across large electric motor populations.
Excellent Corrosion Resistance
Provides protection against rust and corrosion for bearing surfaces in humid and demanding industrial environments — protecting large-frame motor bearings from premature corrosion-related wear.
Excellent Low-Temperature Performance
Maintains bearing protection down to -29°C, ensuring reliable lubrication and motor start-up performance in cold storage, refrigeration and outdoor industrial environments.
Broad OEM Compatibility
Recommended for vertically mounted bearings and large-frame motors across major bearing and electric motor manufacturer specifications — simplifying procurement for large industrial drive applications.
Recommended Applications
Vertically Mounted Motor Bearings
Primary design application — electric motor bearings mounted in a vertical orientation, where the stiffer NLGI 3 consistency prevents grease migration and maintains correct bearing fill over time.
Large-Frame Electric Motors
Large motors where OEM specifications call for a firmer grease consistency than standard NLGI 2 — common on high-output industrial drive motors.
Fin Fan & Pump Bearings
Cooling fan and pump bearing applications operating at elevated temperature where a firmer grease consistency is specified by the OEM.
Sealed-for-Life Bearings
Factory-filled, sealed-for-life ball or roller bearings benefiting from low oil separation and extended lubrication life under continuous operation.
High-Temperature Operation
Ball or roller bearings operating at high temperature where low oil separation is required to maintain consistent lubrication and extend bearing life.
Humid & Wash-Down Environments
Motor bearings in humid or wash-down industrial environments where superior water washout resistance is required to prevent grease loss.
Note on marine and coastal use: Mobil Polyrex EM 103 provides slightly less protection under mild salt-water wash conditions than standard Mobil Polyrex EM. For coastal or marine motor applications, confirm the correct grade with our technical team before specifying.
Polyrex EM 103 vs Polyrex EM — Grade Selection
Both grades use the same advanced polyurea formulation — select by NLGI consistency and bearing orientation specified in your motor OEM manual
Polyrex EM 103 — NLGI 3 (this product)
— Stiffer consistency for vertical mounts & large motors
— Superior oil separation & water washout resistance
— Dropping point: 270°C · Water washout: 0.8 wt%
— Oil separation: 0.1 mass%
— Available: 18kg pail & 180kg drum
Polyrex EM — NLGI 2
— Standard consistency for most motor orientations
— Best mild salt-water wash protection of the two grades
— Dropping point: 260°C · Water washout: 1.9 wt%
— Oil separation: 0.5 mass%
Always confirm the correct grade and consistency from your motor OEM service manual before ordering. Contact Orbit Industrial for grease selection assistance.
Technical Properties
| Property | Test Method | Value |
|---|---|---|
| Grade | — | NLGI 3 |
| Thickener Type | — | Polyurea |
| Colour, Visual | — | Blue |
| Dropping Point | ASTM D2265 | 270°C |
| Penetration, 60X | ASTM D217 | 250 (0.1mm) |
| Penetration Change, 60X–100,000X | ASTM D217 | 40 (0.1mm) |
| Four-Ball Wear Test, Scar Diameter | ASTM D2266 | 0.6mm |
| Lubrication Life @ 177°C | ASTM D3336 | 750+ hrs |
| Oil Separation, 0.25 psi, 24h @ 25°C | ASTM D1742 | 0.1 mass% |
| Water Washout, Loss @ 79°C | ASTM D1264 | 0.8 wt% |
| Copper Strip Corrosion, 24h @ 100°C | ASTM D4048 | 1A |
| Corrosion Preventive Properties | ASTM D1743 | Pass |
| SKF Emcor Rust Test, 10% Synthetic Sea Water | ASTM D6138 | 0, 1 |
| Low Temp Torque, Running, -29°C | ASTM D1478 | 910 g-cm |
| Low Temp Torque, Starting, -29°C | ASTM D1478 | 5840 g-cm |
| Base Oil Viscosity @ 40°C | ASTM D445 | 115 mm²/s |
| Base Oil Viscosity @ 100°C | ASTM D445 | 12.2 mm²/s |
| Viscosity Index | ASTM D2270 | 95 |
Typical properties — not guaranteed specifications. Source: ExxonMobil Product Data Sheet, August 2025.
Pack Sizes & Procurement
Available Pack Sizes
16kg Pail
Workshop & plant supply
Orbit Industrial supplies Mobil Polyrex EM 103 electric motor grease to manufacturing, processing and facilities operations across the Western Cape, Northern Cape, Garden Route and Gauteng. Request a bulk quote →
Technical Documentation
Mobil Polyrex™ EM Series — Technical Datasheet
Electric motor bearing grease series · Orbit Industrial
For Safety Data Sheet (SDS) visit msds.exxonmobil.com →
Orbit Industrial Supplies distributes genuine Mobil Polyrex electric motor greases to manufacturing, processing and industrial operations across South Africa. Mobil Polyrex EM (NLGI 2) → · Full grease range → · Request a quote →

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