Castrol Optigear EP 100
ISO VG 100 gear oil
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Key specs
| Spec | Value | Method |
|---|---|---|
| KV40 | 102 cSt | ASTM D445 |
| KV100 | 11.4 cSt | ASTM D445 |
| Viscosity index | 97 | ASTM D2270 |
| Pour point | -24 °C | ASTM D97 |
| Flash point | 240 °C | ASTM D92 |
| Density at 15 °C | 0.892 g/cm³ | typical |
Grade checks
- KV40 is inside ISO VG 100 (90–110 cSt).
- Computed viscosity index is 98, within 2 points of the listed 97.
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
- Synthetic: Conventional
- AGMA class: AS
- FZG fail stage: >=14
- Copper: 1
- Note: Extreme pressure gear lubricant, mineral oil
Equivalents
| Oil | Score | Why |
|---|---|---|
| Mobil 600 XP 100 | 75 | same ISO 100, VI 97 vs 97, conventional, pour -24 vs -24, flash within 15 °C, AGMA AS, buyable now |
| Shell Omala S2 G 100 | 72 | same ISO 100, VI 100 vs 97, conventional, pour -24 vs -24, flash within 15 °C, AGMA AS, buyable now |
| Shell Omala S2 GX 100 | 68 | same ISO 100, VI 99 vs 97, conventional, pour -24 vs -24, flash within 15 °C, AGMA AS |
| Chevron Meropa 100 | 67 | same ISO 100, VI 100 vs 97, conventional, pour -29 vs -24, flash within 15 °C, AGMA AS |
| Mobil Vacuoline 525 | 53 | same ISO 100, VI 99 vs 97, conventional, pour -24 vs -24 |
Scores use published typical data. This is not an exact equivalent, and it is not an OEM approval. Confirm the substitute with the machine builder.
Documents
- Product data sheet
- Safety data sheet
- Specs last read from the data sheet on 2026-09-09.
Related: Castrol, Optigear EP, viscosity index calculator, ISO / SAE / AGMA chart.
Questions
Is Castrol Optigear EP 100 an ISO VG 100 oil?
Yes. The catalogue lists it as ISO VG 100, which is a kinematic viscosity of 100 cSt at 40 °C, plus or minus 10 percent (90 to 110 cSt). Confirm the current data sheet before you fill a machine.
What is a Castrol Optigear EP 100 equivalent?
Published oils in the same application and grade include Mobil 600 XP 100, Shell Omala S2 G 100, Shell Omala S2 GX 100. The match is from typical data-sheet values, not from an OEM approval. It is not an exact equivalent. Confirm the substitute with the machine builder.
Can Castrol Optigear EP 100 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.
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