Gas Engine Oil

Mobil Pegasus™ 610 Ultra is a high performance biogas oil primarily intended for the lubrication of modern medium and high speed four-cycle engines operating on fuel that contains corrosive materials such as hydrogen sulphide or halogens (compounds containing chlorine, fluorine, etc.). This product is specially developed to cope with agressive gases with high levels of hydrogen sulphide which significantly limits the oil drain intervals and with high levels of siloxanes whose abrasive effects once burnt can significantly increase wear and reduce engine life.

Mobil Pegasus™ 610 Ultra is a 1.0% sulfated ash, high Total Base Number (TBN) gas engine oil with exceptional reserve alkalinity designed to offset the negative effects of these corrosive materials on engine components.

Mobil Pegasus™ 610 Ultra provides excellent anti-wear and especially anti-scuff performance assuring minimal piston scuffing, scoring and cylinder and ring wear. This product can also be used for the lubrication of the reciprocating compressors in landfill and biomass gas applications.

Mobil Pegasus™ 610 Ultra has a high level of wear protection which helps reduce the scuffing of the liners and extend the overhaul periods and significantly longer operating period.

Features and Benefits

Mobil Pegasus™ 610 Ultra gas engine oil provides an additional level of protection in those applications using highly contaminated fuel where piston scuffing, high deposit formations and very short drain interval were observed.

Features Advantages and Potential Benefits
High TBN and Reserve Alkalinity Controls wear and corrosion when using contaminated gas
Protects valve seats and faces on four-cycle engines
Controls combustion chamber ash formation and improves spark plug performance
Outstanding Anti-wear and Anti-scuff Properties Lower wear of engine components
Reduced scuffing of liners in highly loaded gas engines
Provides excellent break-in protection
Excellent Oxidation and Chemical Stability Cleaner engines
Extended oil drain intervals even with highly contaminated fuels
Reduced oil filter costs
Excellent resistance to oxidation and nitration
Effective Corrosion Resistance Reduces valve guide wear in four-cycle gas engines
Protects bearings and internal components
Exceptional Detergent / Dispersant Properties Neutralises formation of acids in the oil
Protection of upper cylinder and valve train components


Gas engines operating on fuel that contains moderate to high levels of hydrogen sulphide (H2S) and high levels of siloxanes which turn to silicon dioxide in the combustion process causing significant deposits and liner wear.

Engines operating on fuel containing other corrosive components such as TOHCl (Total Organic Halides as Chloride)

Reciprocating compressors operating on natural gas that contains sulphur or halogens

High output or naturally aspirated engines operating at or in excess of rated capacity under high temperatures

Properties and Specifications

Grade SAE 40
Kinematic Viscosity @ 100 C, mm2/s, ASTM D445 12.9
Viscosity Index, ASTM D2270 107
Density @ 15.6 C, g/ml, ASTM D1298 0.875
Pour Point, °C, ASTM D97 -30
Flash Point, Cleveland Open Cup, °C, ASTM D92 259
Ash, Sulfated, mass%, ASTM D874 1.0
Total Base Number, mgKOH/g, ASTM D2896 10.5

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.