Gas Engine Oil

Mobil Pegasus 705 is a premium high performance SAE 40 gas engine oil formulated to lubricate a wide range of natural gas fuelled engines. It is recommended for the newer stoichiometric and lean burn high-speed four-cycle engines that are sensitive to valve face and seat wear. This oil is also recommended for the lubrication of the gas compressors and wide range of engines requiring low ash oil. Pegasus 705 is formulated from select high quality, mineral base oils and an advanced technology additive system engineered to provide excellent protection of engine and compressor components and reduced levels of combustion chamber deposits. It exhibits exceptional chemical stability and resistance to oxidation and nitration resulting in longer oil life and lower filter replacement costs. These performance advantages combined with outstanding detergency and dispersancy properties minimise the formation of ash and carbon deposits that could result in poor engine performance and detonation.

Pegasus 705 exhibits excellent anti-corrosion properties that prevent corrosive wear in cylinders, valve areas and bearings resulting in longer engine life. Its high level of anti-wear performance reduces wear of rings, liners, and bearings. It also provides exceptional valve seat and face protection and reduces the wear and deposit formation in the critical valve guides of highly loaded turbocharged four-cycle engines.

Features and Benefits

Mobil Pegasus 705 gas engine oil provides for cleaner engines, lower wear rates and improved engine performance. The product is particularly beneficial in increasing valve life and engine performance in the newer lean-burn, design high-speed four-cycle engines operating under heavy loads. The result is reduced maintenance costs and improved production capacity. The excellent chemical and oxidation stability results in longer drain periods and reduced filter costs. Pegasus 705 reduces ash and carbon formation in combustion chambers resulting in lower maintenance costs while improving engine performance and reducing fuel costs.

Features Advantages and Potential Benefits
Excellent Anti-wear and Anti-scuff Properties Lower wear of engine components

Reduced scuffing of liners of highly loaded gas engines

Provides excellent break-in protection

Exceptional Oxidation and Chemical Stability Cleaner engines

Extended drain intervals

Reduced filter costs

Excellent resistance to oxidation and nitration

Reduces coking and formation of undercrown deposits

Low Ash Formulation Reduces valve seat, face and guide wear

Controls combustion chamber ash formation and improves spark plug performance

Improved engine performance

Lower fuel costs

Corrosion Resistance Reduces valve guide wear in four stroke-cycle gas engines

Protects bearings and internal components

Outstanding Detergency and Dispersancy Properties Cleaner engines

Improved upper cylinder performance

Longer filter life

Lower maintenance costs


• High-speed lean-burn and stoichiometric gas engines sensitive to vlve seat recession

• Crankcases and power cylinders of spark-ignited two and four-stroke cycle gas engines

• Recommended for applications requiring low ash formulations

• Reciprocating natural gas compressor cylinders

• High output or ambient rated engines operating at or in excess of rated capacity under high temperatures

• Engines operating on fuel containing low levels of hydrogen sulphide

Specifications and Approvals

This product has the following approvals:
INNIO JENBACHER TI 1000-1109 (Class A fuel gas) Type 9 engines
INNIO JENBACHER TI 1000-1109 (Class A fuel gas, Series 2, 3, 4 & 6)
INNIO JENBACHER TI 1000-1109 (Class B fuel gas, Series 4 & 6)
MAN M 3271-2
MTU MTU Gas Engines S4000 L61, L62, L63, L64 using natural gas
MTU Onsite Energy Series 400 Gas Engines
MWM GmbH TR 0199-99-2105, TCG2016 < 48.5 kWe / cyl. TCG2020 < 95.0 kWe / cyl. TCG2032 < 260.0 kWe / cyl.
This product meets or exceeds the requirements of:

Properties and Specifications

Grade SAE 40
Ash, Sulfated, mass%, ASTM D874 0.5
Flash Point, Cleveland Open Cup, °C, ASTM D92 252
Kinematic Viscosity @ 100 C, mm2/s, ASTM D445 13.2
Kinematic Viscosity @ 40 C, mm2/s, ASTM D445 126.2
Pour Point, °C, ASTM D97 -18
Specific Gravity, 15.6 C/15.6 C, ASTM D1298 0.887
Total Base Number, mgKOH/g, ASTM D2896 5.6
Viscosity Index, ASTM D2270 98

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.