Product Description

Mobilgard L540 by ExxonMobil is a superior quality, extra high performance marine diesel engine cylinder oil. This unique formulation has been specifically developed for engines running in a low sulphur heavy fuel oil (HFO) environment. This cylinder lubricant provides maximum protection from adhesive and corrosive wear at the higher operating temperatures and pressures of today’s modern crosshead engines, for maximum reliability. It employs additives with greater therrmal stability and superior acid-corrosion protection. It has an optimum viscosity of over 20 cSt. at 100ºC and low volatility for best lubricant distribution and film retention. Through the use of unique formulation technology, the higher viscosity is attained with little or no use of thermally less stable, deposit-producing bright stock. Advanced technology at the 40 TBN alkalinity level in Mobilgard L540 has demonstrated excellent ring and liner wear protection and cleanliness under sustained operation with fuel sulphur levels from less than 0.3% up to 1.5%.

Features and Benefits

Mobilgard L540 cylinder oil offers the following features and potential benefits:

Features Advantages and Potential Benefits
Excellent thermal and oxidation stability Reduced deposits and sludge formation

Extended oil life

Cleaner engine reduces lay-up time required for overhauls

Exceptional antiwear properties Reduced liner and ring wear

Excellent anti-scuffing control

Outstanding detergency capability Superior piston and liner cleanliness increases combustion efficiency and extends periods between piston overhauls
High Viscosity Index and stable basestocks Reduced cylinder oil consumption


Mobilgard L540 has been developed for marine crosshead engines with increased power and fuel efficiency. Such engines exhibit higher temperatures and pressures in the cylinder, which reduce the lubricant’s viscosity and increase the loads which it must withstand. Longer piston strokes have greatly increased the amount of surface to be protected and the amount of time the lubricant must withstand the severe cylinder temperatures and corrosive sulphur acids. Mobilgard L540 has also demonstrated superior performance in earlier engine designs.

To ensure achieving the maximum equipment life possible, particular attention should be paid to the manufacturer’s special recommendations regarding the running-in of new rings and liners.

Mobilgard L540 was specially formulated for use in applications with fuel sulphur levels ranging from less than 0.3% up to 1.5%. Applications where the sulphur level is above 1.5% require special consideration and should be discussed with your ExxonMobil representative.

Appropriate feed rates should be verified in all cases by through-the-ports inspection of liners to ensure adequate oil film.

Properties and Specifications

Grade SAE 50
Flash Point, Cleveland Open Cup, °C, ASTM D92 264
Kinematic Viscosity @ 100 C, mm2/s, ASTM D445 21
Kinematic Viscosity @ 40 C, mm2/s, ASTM D445 236
Pour Point, °C, ASTM D97 -6
Total Base Number, mgKOH/g, ASTM D2896 40
Viscosity Index, ASTM D2270 105
Density @ 15 C, kg/m3, ASTM D4052 917.0

Health and safety

Health and Safety recommendations for this product can be found on the Material Safety Data Sheet (MSDS) @


It cannot be guaranteed that the product information given above is up to date. For the latest version of the Product Data Sheet we refer to the product library of ExxonMobil.