Low-temperature bearing grease & starting torque
A bearing that runs acceptably when warm may struggle at a cold start.
On this page8 sections ⌄
What to check
Record the cold-start case
Use the lowest soak temperature, starting speed and available drive torque, not only the normal operating temperature.
Check lubricant test data
Low-temperature torque and flow data for the exact lubricant are more useful than assuming any synthetic product will work. Check seal drag and lubricant delivery too.
Validate the transition
Confirm that the same lubricant supports the warm running load. Reducing viscosity for starting must not leave the hot operating film inadequate.
Direct answer
Check cold starting torque and lubricant delivery at the lowest expected temperature, then verify the warm-running film requirement. A synthetic label or a softer consistency alone cannot prove that both conditions are satisfied.
Same base-oil viscosity, different measured low-temperature torque
Mobil Polyrex product data: ASTM D1478 at −29 °C. Values are for the stated test, not motor starting torque or a prediction for your bearing.
On a small screen, scroll the table sideways to read every column.
| Product | NLGI | Starting torque (g·cm) | Running torque (g·cm) |
|---|---|---|---|
| Mobil Polyrex EM | 2 | 3630 | 405 |
| Mobil Polyrex EM 103 | 3 | 5840 | 910 |
The source reports base-oil viscosity at 40 °C as 115 mm²/s for both products. These test results show why that single viscosity value is not a complete cold-start specification. Compare equivalent test conditions and retain the actual unit; g·cm is not N·m.
Record both ends of the temperature cycle
| Condition | Required evidence |
|---|---|
| Lowest soak temperature | Available start-up torque and the exact lubricant's low-temperature data |
| Delivery lines and reservoir | Pumpability and verified supply at the same cold condition |
| Normal warm operation | Viscosity and film requirement for actual load and speed |
| Start-stop sequence | Permitted acceleration and warm-up conditions |
| Seals and other components | Their temperature and material limits |
The table does not endorse a product for an unspecified cold-weather motor. A change intended to ease starting still needs compatibility review and adequate lubrication once the machine is warm.
Reference scope
Manufacturer and technical-institute records reviewed for this page: Mobil Polyrex EM / EM 103 product data; JTEKT lubricant selection reference; retrieved 2026-10-01 UTC. Values are a dated reference snapshot, not an OEM approval or a substitute for the current technical and safety documents. Original source addresses and retrieval evidence are retained in the private content audit.
Continue with real catalogue data
Preserve the full model, source description and unknown fields when making your shortlist. This reference website does not sell bearings or certify a replacement.
Related questions and tools
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Read and apply →Reference basis & data limits
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Selection workflows and catalogue grouping are BearingScope editorial aids. Verify the current drawing and application requirements before using a candidate. Missing database information is not converted into an assumed match.