Mobilgard 540 AC
Mobilgard 540 AC is an advanced 40 BN cylinder oil developed for slow-speed two-stroke marine engines operating on fuels with up to 1.50% sulphur, including LNG, ethane, methanol and LPG. The formulation uses ExxonMobil’s balanced additive technology to deliver strong cleanliness, deposit control and wear protection across a wide range of modern marine fuel types. The product has been LNG validated by WinGD and holds Category II status from MAN Energy Solutions for use in dual-fuel engines.
One of the key advantages of Mobilgard 540 AC is its exceptional cleanliness performance. The high detergency level helps reduce deposits and combat scuffing-related wear associated with low sulphur and alternative fuels. This supports cleaner piston and liner surfaces and improved lubrication efficiency.
Mobilgard 540 AC also provides excellent thermal and oxidative stability. The formulation maintains performance under severe operating conditions while protecting components from wear and deposit formation. This contributes to extended engine life and improved operational reliability.
Another important benefit is its wide fuel compatibility. Mobilgard 540 AC is suitable for slow-speed two-stroke engines operating on LNG, distillate fuels, methanol and very low sulphur fuel oils (VLSFOs). The product is approved for use in MAN ES and WinGD engines, including dual-fuel variants.
Mobilgard 540 AC can be used with cylinder condition monitoring programmes to optimise feed rates and improve engine protection. This helps simplify operations, reduce maintenance and enhance vessel reliability.
Physical characteristics include SAE 50 viscosity grade with kinematic viscosity of approximately 218 mm²/s at 40°C and 19 mm²/s at 100°C. Mobilgard 540 AC has density of approximately 0.904 at 15°C, flash point of approximately 207°C and pour point of approximately −30°C. Total base number is approximately 40, providing balanced acid neutralisation and deposit control.
