Castrol Cyltech 70 Cylinder Oil
Specifications
| OEM | Castrol Marine | |
|---|---|---|
| Product type | Marine two-stroke crosshead engine cylinder oil | |
| Base Number (BN) | 70 mg KOH/g | |
| SAE viscosity grade | SAE 50 | |
| Kinematic viscosity @ 100°C | 19.5 mm²/s | |
| Density @ 15°C | 0.934 g/ml | |
| Flash point (PMCC) | >190°C | |
| Pour point | -9°C | |
| Intended fuel / application | Residual fuels with sulphur content typically 1.0-3.5% (HSFO); usable across 0.1-3.5% S when feed rate is adjusted | |
| Engine-OEM approvals | Holds 'No Objection' status with the principal manufacturers of crosshead two-stroke engines under their current oil recommendation lists (no individual MAN Energy Solutions / WinGD names listed in the PDS) |
Technical notes
Cyltech 70 is an SAE 50 cylinder lubricant for low-speed marine crosshead two-stroke engines, carrying a BN of 70 mg KOH/g. Per the Castrol PDS, this alkalinity reserve is matched to medium-to-high-sulphur residual fuels in the 1.0-3.5% S band, neutralising acidic combustion products while an ashless dispersant keeps ring zones, ports and under-piston spaces clean. It can serve a wider 0.1-3.5% S range when feed rates are tuned. Within the Cyltech range it sits between the low-BN 40SX (lower-sulphur/dual-fuel) and BN 100 grades. The original formulation was superseded in 2025 by Cyltech 70f. Final grade and feed-rate selection must be confirmed with the engine OEM and Castrol for the specific engine, fuel and operating profile.
Compliance
Castrol PDS reports Cyltech 70 holds 'No Objection' status with the principal crosshead two-stroke engine manufacturers under their current oil recommendation lists; specific OEM approvals must be verified with Castrol and the engine builder.
Compatibility
Other parts in this series
Related
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Frequently asked questions
- What is the Base Number of Castrol Cyltech 70?
- Castrol's product data sheet lists a Base Number (BN) of 70 mg KOH/g, providing the alkalinity reserve to neutralise acids from medium-to-high-sulphur residual fuels.
- What fuels and engines is Cyltech 70 intended for?
- It is a SAE 50 cylinder oil for low-speed marine crosshead two-stroke engines burning residual fuels with sulphur typically 1.0-3.5% (HSFO), and is usable across 0.1-3.5% S when feed rates are adjusted appropriately.
- Is Cyltech 70 still current?
- The original Cyltech 70 formulation was superseded in 2025 by Cyltech 70f. Confirm the correct current grade and feed rate with the engine OEM and Castrol.
Castrol Cyltech 70 Cylinder Oil
No public pricing — quoted per request