Castrol Optigear EP 46
ISO VG 46 gear oil
Buy
No retailer listing is on file for this oil. Email us and we will point you at a distributor. A quote form, and Zoro, Walmart, eBay, Grainger, MSC and Global Industrial, wait on programs that are not connected yet.
As an Amazon Associate, Evolvent Design earns from qualifying purchases. McMaster-Carr links are not affiliate links.
Key specs
| Spec | Value | Method |
|---|---|---|
| KV40 | 46 cSt | ASTM D445 |
| KV100 | 6.8 cSt | ASTM D445 |
| Viscosity index | 103 | ASTM D2270 |
| Pour point | -30 °C | ASTM D97 |
| Flash point | 220 °C | ASTM D92 |
| Density at 15 °C | 0.88 g/cm³ | typical |
Grade checks
- KV40 is inside ISO VG 46 (41.4–50.6 cSt).
- Computed viscosity index is 102, within 2 points of the listed 103.
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: >=12
- Copper: 1
- Note: Extreme pressure gear lubricant, mineral oil
Equivalents
| Oil | Score | Why |
|---|---|---|
| Mobil Mobil SHC 625 | 20 | same ISO 46, VI 161 vs 103, flash within 15 °C, AGMA AS, buyable now |
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 46 an ISO VG 46 oil?
Yes. The catalogue lists it as ISO VG 46, which is a kinematic viscosity of 46 cSt at 40 °C, plus or minus 10 percent (41.4 to 50.6 cSt). Confirm the current data sheet before you fill a machine.
What is a Castrol Optigear EP 46 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 EP 46 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
The report is stored for review. It does not change the page by itself, and it is not emailed anywhere yet.