Cold corrosion eliminated and performance optimised for a Wärtsilä RT Flex 82-T engine

cargo ship port

With market conditions continuing to challenge operators, the discovery of severe cold corrosion in the Wärtsilä RT Flex 82-T engine of a container vessel was a major concern. Despite using a 70 BN cylinder oil at an elevated feed rate of 1.3g/kWh, low residual BN levels had resulted in peeling of the chrome coating on the piston rings. This was causing costly detrimental liner wear and scuffing. The vessel, which was slow steaming at 20-60 per cent of maximum continuous rating, was running on heavy fuel oil with an average sulphur content of between 2.3 and 3.4 per cent.


Onboard trials were conducted by ExxonMobil engineers who implemented the Mobil Serv℠ Cylinder Condition Monitoring service, a proactive tool for the management of slow speed cylinder lubrication. Used in association with MobilGard™ cylinder oils, it can enable significant lubricant savings to be realised in a controlled and managed manner. A switch to Mobilgard™ 5100, a 100 BN cylinder oil, was recommended. The oil is proven to provide protection to slow-speed two-stroke marine engines running on high-sulphur fuel.


The change to Mobilgard 5100 cylinder oil helped optimise engine performance, increased vessel reliability, and ultimately reduced running and repair costs. Switching to the 100 BN lubricant mitigated cold corrosion and contributed to excellent engine cleanliness.

It also resulted in a valuable saving in cylinder oil consumption – the feed rate was reduced by 34 per cent compared with previous performance. Piston rings and piston ring top lands showed significantly reduced deposits while low iron levels in scrape down samples indicated minimum liner wear. As a result, maintenance expenditure was cut and the time between engine overhauls was extended.