How do I pick a Mobilgard cylinder-oil grade?

By base number matched to fuel sulphur and your engine OEM's approval — a high-BN grade for HSFO, a lower-BN grade for VLSFO/LSFO. Confirm the exact grade with ExxonMobil for your fuel and engine.

Can one Mobilgard grade cover all fuels?

Some grades have a usable range, but matching BN to the fuel is what protects the liner. Operators switching between high- and low-sulphur fuel typically adjust grade and/or feed rate.

Do Mobilgard cylinder oils carry OEM approvals?

Yes — the major two-stroke engine makers approve specific grades. Always check the current approval for your engine model before changing oil.

Mobilgard Two-Stroke Cylinder Oils

Mobilgard two-stroke cylinder oils are the once-through lubricants injected onto the liner of slow-speed crosshead main engines, where their alkaline reserve (base number, BN) neutralises the sulphuric acid formed as fuel sulphur burns. The range is built around BN so that operators can match the oil to the fuel: higher-BN grades for high-sulphur fuel oil (HSFO), and lower-BN grades for the very-low and low-sulphur fuels (VLSFO and LSFO) that became standard after the IMO 2020 sulphur cap. Choosing within the range is a balance — too little BN for the fuel allows cold-corrosion of the liner, while too much BN for a low-sulphur fuel leaves unreacted additive that forms deposits and can cause bore polishing. Cylinder condition is managed by both grade selection and feed rate, within the engine maker's guidance. Each grade we list carries datasheet data — base number, SAE viscosity grade, application and engine-OEM approvals — and the specific choice should always be confirmed against the engine OEM's approval and ExxonMobil's recommendation for the fuel and engine model in service.

Matching grade to fuel

Within the Mobilgard cylinder-oil range, the grade is chosen primarily by base number against the fuel sulphur: a high-BN grade for HSFO operation and a lower-BN grade for VLSFO/LSFO. Ships that switch fuels across ECA boundaries manage the transition with grade and feed-rate choices.

Approvals and feed rate

Mobilgard cylinder oils carry approvals from the major two-stroke OEMs (MAN Energy Solutions, WinGD). Feed rate is set within the engine maker's minimum and adjusted with load, fuel sulphur and observed liner condition — see the cylinder-oil BN selection guide for the detail.

Maintenance notes

Match cylinder-oil base number to the fuel in use and never run a low-BN oil on high-sulphur fuel. Confirm the grade against the engine OEM approval and ExxonMobil guidance, and verify feed rate against the engine maker's service letters before changing grade.

Drawing & section references

High BN Cylinder oils for high-sulphur fuel (HSFO)
Low BN Cylinder oils for VLSFO / LSFO operation

Parts & spares

Fitted on

Chemical tanker spares

Multi-part RFQ — no public pricing.

Frequently asked questions

How do I pick a Mobilgard cylinder-oil grade?: By base number matched to fuel sulphur and your engine OEM's approval — a high-BN grade for HSFO, a lower-BN grade for VLSFO/LSFO. Confirm the exact grade with ExxonMobil for your fuel and engine.
Can one Mobilgard grade cover all fuels?: Some grades have a usable range, but matching BN to the fuel is what protects the liner. Operators switching between high- and low-sulphur fuel typically adjust grade and/or feed rate.
Do Mobilgard cylinder oils carry OEM approvals?: Yes — the major two-stroke engine makers approve specific grades. Always check the current approval for your engine model before changing oil.