Gas Engine Oil

Mobil Pegasus™ 801 SAE 30 is a premium performance gas engine oil intended for the lubrication of all classes of gas engines operating at low, medium and high speeds where low ash or ashless oils are recommended. It provides outstanding engine cleanliness and performance by helping to prevent the formation of carbon and ash deposits on pistons, in ring belt areas, on exhaust and intake ports, on valves and valve stems and in combustion chambers. Mobil Pegasus 801 SAE 30 also reduces the potential for port carboning of two-cycle gas engines. It minimizes engine wear and protects valve faces, seats and guides of turbocharged, four-cycle engines. Mobil Pegasus 801 SAE 30 provides exceptional protection against scuffing in demanding engine applications and also provides excellent protection against corrosion of internal engine components. Filter and oil life can be extended and the high performance capability of the Mobil Pegasus 801 SAE 30 can also help to extend the time between engine maintenance and overhaul periods.


The Mobil Pegasus 801 SAE 30 is the latest generation of ashless detergent and anti-scuff gas engine oil formulated from highly refined base oils and an advanced technology additive system. It is engineered to provide a high level of chemical and thermal stability resulting in cleaner engines and higher engine performance. Mobil Pegasus 801 SAE 30 provides exceptional cleanliness and optimum wear protection in the most severe applications, without the disadvantage of increased ash deposits.


Equipment lubricant recommendations

Data sheets

Features and Benefits

Mobil Pegasus 801 SAE 30 provides outstanding performance in both two- and four-cycle gas engines making it a good choice for all applications where ashless and low-ash oils are recommended. Its advanced additive system protects high BMEP engines against scuffing, scoring and wear particularly during critical break-in periods. This performance can help to provide long engine life and low maintenance costs. Mobil Pegasus 801 SAE 30 has demonstrated outstanding performance over an exceptionally wide range of engines and operating conditions. Where mixed engines are in service Mobil Pegasus 801 SAE 30 provides a single product which simplifies inventory and reduces the potential for product misapplication.



Advantages and Potential Benefits

Outstanding Oxidation Stability

Longer engine and oil life

Cleaner engines

Extended filter life

Advanced Technology Very Low Ash Formulation

Lower levels of port carboning (two-cycle engines)

Reduced valve and combustion chamber ash and carbon build-up

Longer spark plug life

Outstanding Anti-wear and Anti-scuff Protection

Less engine wear

Increased engine life

Excellent break-in protection for high BMEP engines

Exceptional Nitration Resistance

Less engine sludging

Improved filter life

Reduced engine deposits

High Level Corrosion Protection

Protects engine components against corrosive wear

Longer engine life and lower maintenance costs



     •  Mobil Pegasus 801 SAE 30 is recommended for the lubrication of the crankcase, power cylinders, and compressor cylinders of spark-ignited, two- and four-cycle gas engines operating on clean fuel.

     •  Ideal for engines that drive generators for power production or gas compressors in gathering, transmission, storage, and distribution of natural gas.

     •  Ebulliently cooled gas engines

     •  Engines in remote locations which operate virtually unattended for long periods. In many cases, the engines are operated at, or in excess of full-rated output, while other applications are intermittent or stand-by service. Reliability, is therefore essential.

     •  Mobil Pegasus 801 SAE 30 shows excellent results in multipurpose applications, particularly involving highly turbocharged engines requiring anti-scuff protection for cylinder liners and piston skirts.

     •  When natural or petroleum gas is being compressed and is dry and free of suspended liquids or corrosive components, the compressor cylinders usually are lubricated with the same oil as the engine crankcase. Mobil Pegasus 801 SAE 30 has been successful in this service.



Specifications and Approvals


Mobil Pegasus 801 SAE 30 recommended for use in applications requiring:

     •  Ashless or low-ash gas engine oils

     •  Outstanding anti-scuff protection

     •  Wide range of mixed gas engine designs



Properties and Specifications



SAE 30

Kinematic Viscosity @ 40 C, mm2/s, ASTM D445


Kinematic Viscosity @ 100 C, mm2/s, ASTM D445


Viscosity Index, ASTM D2270


Ash, Sulfated, mass%, ASTM D874


Total Base Number, mgKOH/g, ASTM D2896


Pour Point, °C, ASTM D97


Flash Point, Cleveland Open Cup, °C, ASTM D92


Specific Gravity, 15.6 C/15.6 C, ASTM D1298



Health and safety

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

  • Corrosion protection
  • Enhanced wear protection
  • Oxidation resistance