Slow-speed engine oil
Explore our range of slow-speed engine oils, Castrol Cyltech. Designed to help prevent corrosion and deposits, delivering 2-stroke engine cleanliness.
Forward in protection, performance, and reliability
The marine industry is changing fast. New engine designs, the transition to low-sulphur fuel oil (VLSFO), and the rise of dual-fuel engines are reshaping operational demands. Because of this, the focus has shifted from tackling cold corrosion to preventing harmful deposits – a shift that has exposed the limits of many traditional 40 BN cylinder oils.
Left unprotected, excessive deposits can lead to wear, efficiency loss and costly downtime – putting critical operations at risk.
Castrol’s high-performance slow-speed engine oils have been designed to meet these demands head-on. Castrol Cyltech helps to prevent deposits and corrosion in your slow-speed engines.
Optimal solutions for 2-stroke engines
To tackle the evolving industry, Everllence introduced the Category II performance level – with a sharper focus on cleanliness and deposit control. This benchmark reflects the industry’s need for higher-performing lubricants that deliver protection and reliability across today’s diverse fuel types.
The Castrol Cyltech range not only meets Everllence requirements, but also holds multiple OEM approvals. Trusted by operators worldwide, the range gives you the confidence to perform – voyage after voyage.
Confidence in every voyage
Learn more about our Castrol Cyltech range – delivering the right balance of protection, performance, and efficiency for modern engines.
Delivering 2-stroke engine cleanliness
The Castrol Cyltech range of cylinder oils has been formulated to deliver 2-stroke engine cleanliness and provide excellent control of piston ring and cylinder liner wear. Our products are available across a range of different base numbers spanning 40 to 140 BN. With approval from the major OEMs, the Cyltech range is designed to meet the needs of your slow-speed engine.
Castrol Cyltech has a long history supporting 2-stroke reliability
Our cylinder oil is trusted by 500+ marine customers
Used in over 8,000 vessels
Annually, Cyltech has performed for 34 million voyage hours†
Approvals achieved as a result of 75,000 hours of filed testing
Available in over 800 ports worldwide
Cyltech 40 XDC
- Category II 40 BN cylinder oil*
- Formulated for increased cleanliness in combustion cylinder
- Performance equal to or better than a category II 100 BN cylinder oil
- Approved across all MAN ES engines and recommended for Mark 9 and higher
- Category II lubricant for LNG and methanol**
No objection letters
- Everllence
- Win GD
Marine fuels <0.5% sulphur
- MGO: marine gas oil, <0.1% sulphur (distillate)
- ULSFO: ultra low sulphur fuel oil, <0.1% sulphur (residual)
- VLSFO: very low sulphur fuel oil, <0.5% sulphur (residual)
Cyltech 40SX
- Bespoke detergency system for engine cleanliness
- Very good overall performance, especially deposit control
- Excellent performance at optimised feed rates
- Approved for use in Win GD DF dual fuel engines running on LNG
- Proven performance on biofuels (B30 and B50)***
No objection letters
- Everllence
- Win GD DF
- JEC
Marine fuels <0.5% sulphur
- MGO: marine gas oil, <0.1% sulphur (distillate)
- ULSFO: ultra low sulphur fuel oil, <0.1% sulphur (residual)
- VLSFO: very low sulphur fuel oil, <0.5% sulphur (residual)
Cyltech 70f
- Good performance at high temperatures
- Lubrication of low speed crosshead engines
- Suitable for use with compliant fuel and HSFO, subject to OEM recommendations and technical advice
No objection letters
- Everllence
- Win GD
- JEC
Marine fuels <0.5% sulphur
- MGO: marine gas oil, <0.1% sulphur (distillate)
- ULSFO: ultra low sulphur fuel oil, <0.1% sulphur (residual)
- VLSFO: very low sulphur fuel oil, <0.5% sulphur (residual)
HSFO with scrubbers >0.5% sulphur
- HSFO: high sulphur fuel oil
Cyltech 100f
- Protection against corrosive wear
- Excellent control of piston ring and cylinder liner wear
- Helps extend periods between unit overhauls
- Granted category II status – latest performance category from MAN ES
No objection letters
- Everllence
- Win GD
- JEC
HSFO with scrubbers >0.5% sulphur
- HSFO: high sulphur fuel oil
Cyltech 140
- Improved protection of cylinder liners in engines operating under corrosive conditions with lower feed rates compared to 100 BN oils
- Protection against corrosive wear
- Excellent control of piston ring and cylinder liner wear
- Granted category II status – latest performance category from MAN ES
No objection letters
- Everllence
HSFO with scrubbers >0.5% sulphur
- HSFO: high sulphur fuel oil
