Castrol Optigear BM 3000
Extreme pressure gear oil
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Key specs
| Spec | Value | Method |
|---|---|---|
| KV40 | 3000 cSt | ASTM D445 |
| KV100 | 119.8 cSt | ASTM D445 |
| Viscosity index | 110 | ASTM D2270 |
| Pour point | — | ASTM D97 |
| Flash point | 220 °C | ASTM D92 |
| Density at 15 °C | 0.93 g/cm³ | typical |
Grade checks
- 3000 is the maker's grade, not an ISO VG.
- Computed viscosity index is 116 from the stored KV40 and KV100 (ASTM D2270). The listed index is 110, more than 2 points away.
Viscosity and temperature
ASTM D341 (Walther) fitted to the published KV40 and KV100. It is an interpolation between those two points, and it is not meaningful below the pour point. Move the control to read a temperature.
Classification
- Category: Gear
- Attribute: Extreme Pressure
- Synthetic: Conventional
- AGMA class: AS
- FZG fail stage: >=12
- Copper: Unlisted
- Note: For spur and bevel gear units, including severe operating conditions
Sulfur, EP additives and yellow metal
Extreme-pressure gear oils use sulfur compounds so steel teeth do not weld under shock. That same sulfur can tarnish or pit copper, brass and bronze: a bronze worm wheel, a brass cage, a cooler tube. ASTM D130 sits a polished copper strip in the oil and scores the colour. 1A and 1B are the ratings to keep when yellow metal shares the oil. The strip below is that test at room temperature.
How lubricant-induced copper corrosion works
Equivalents
No other brand in this catalogue passes the equivalents filters for this oil.
Documents
- Product data sheet
- Safety data sheet
- Specs last read from the data sheet on 2026-09-09.
Related: Castrol, Optigear BM, viscosity index calculator, ISO / SAE / AGMA chart.
Questions
Is Castrol Optigear BM 3000 an ISO VG 3000 oil?
The row is filed under 3000, which is the maker's grade and not an ISO VG. ISO 3448 does not define VG 3000.
What is a Castrol Optigear BM 3000 equivalent?
No other brand in this catalogue clears the equivalents bar for this oil yet (same application, same grade, compatible base oil, and a score of 60 or more). That is not proof that nothing else works. Check the machine manual.
Can Castrol Optigear BM 3000 be mixed with another oil?
Mixing two oils that share a base family is sometimes done and sometimes a mistake. Do not mix this oil with a PAG. For any other mix, follow the maker's change-over guidance and the machine manual.
Report a data error
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