Universal oils are not unrestricted usable
At slow steaming cold corrosion can occur – Castrol sees concerns by specifications given from the engine manufacturers confirmed.
Many shipping owners go for slow steaming. But to avoid long term damages by slow steaming particular adjustments must be done. One aspect is the use of optimized lubricating oils. A possible problem is cold corrosion. The lubricating oil manufacturer, e.g., Castrol Marine assumes that, during slow steaming, cold corrosion can happen if lube oils with lower base numbers (BN) come together with fuels with higher sulphur content. “We always point out that oils with lower BN are unsuitable for slow steaming with modern diesel engines. Both market leading OEM’s have now created specific guide lines, which go along with our experiences”, says Castrol manager Paul Harrold. They recommend their customers to coordinate the use of lube oils with engine type and working conditions. Last May Castrol presented some case studies. These figures underline the experience that lube oils with a higher BN reduce the corrosive wear and also lower the consumption. Also MAN and Wärtsilä made the same experiences. The Finnish engine manufacturer withdraw recently the permission for many of their engine types which rund on heavy fuel oils with a sulphur content above 2.5 %, says Castrol. “According to the latest declaration of no-objection for suppliers lube oils in the middle BN-area may be used on all Wärtsilä RTA-, RT-flex and W-Xengines as well as on Sulzer 2-stroke engines with heavy fuels and sulphur content of not more than 0.5%”.
Marine engines should be adjusted for the permanent slow steaming operation
“MAN Diesel&Turbo already has withdrawn cylinder oils in the middle BN-class out of their permission list”, says David Goosey, CEO and sales manager of Castrol Marine. “With this limitation done by Wärtsilä, the use of lube oils in the middle BN-class, is quasi excluded for fuels used on engines outside the ECA’s.”
image: PPM News Service