Mobil Pegasus™ 801

Mobil industrial , Lithuania

Gas Engine Oil

Product Description

Mobil Pegasus™ 801 is an SAE 40 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 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 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 can also help to extend the time between engine maintenance and overhaul periods.

The Mobil Pegasus 801 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 provides exceptional cleanliness and optimum wear protection in the most severe applications, without the disadvantage of increased ash deposits.


Features and Benefits

Mobil Pegasus 801 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. It's 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 has demonstrated outstanding performance over an exceptionally wide range of engines and operating conditions. Where mixed engines are in service Mobil Pegasus 801 provides a single product which simplifies inventory and reduces the potential for product misapplication.

FeaturesAdvantages and Potential Benefits
Outstanding Oxidation StabilityLonger engine and oil life
Cleaner engines
Extended filter life
Advanced Technology Very Low Ash FormulationLower 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 ProtectionLess engine wear
Increased engine life
Excellent break-in protection for high BMEP engines
Improved ring, piston and liner life
Exceptional Nitration ResistanceLess engine sludging
Improved filter life
Reduced engine deposits
High Level Corrosion ProtectionProtects engine components against corrosive wear
Longer engine life and lower maintenance costs



  • Mobil Pegasus 801 is intended 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 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 oils show excellent results in multipurpose natural gas engine 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 has been successful in this service.


Specifications and Approvals

Pegasus 801 recommended for use in applications requiring:
Ashless or low-ash gas engine oils
Outstanding anti-scuff protection
Wide range of mixed gas engine designs


Typical Properties

Pegasus 801 
SAE Grade40
Viscosity, ASTM D 445 
cSt @ 40º C125
cSt @ 100º C13.2
Viscosity Index, ASTM D 227097
Sulfated Ash, wt%, ASTM D 8740.13
Total Base #, mg KOH/g, ASTM D 28962.2
Pour Point, ºC, ASTM D 97-15
Flash Point, ºC, ASTM D 92249
Density @15º C kg/l, ASTM D 12980.886


Health and Safety

Based on available information, this product is not expected to produce adverse effects on health when used for the intended application and the recommendations provided in the Material Safety Data Sheet (MSDS) are followed. MSDS's are available upon request through your sales contract office, or via the Internet. This product should not be used for purposes other than its intended use. If disposing of used product, take care to protect the environment.

The Mobil logotype, the Pegasus design and Delvac are trademarks of ExxonMobil Corporation, or one of its subsidiaries.



Typical Properties are typical of those obtained with normal production tolerance and do not constitute a specification.  Variations that do not affect product performance are to be expected during normal manufacture and at different blending locations.  The information contained herein is subject to change without notice. All products may not be available locally. For more information, contact your local ExxonMobil contact or visit
ExxonMobil is comprised of numerous affiliates and subsidiaries, many with names that include Esso, Mobil, or ExxonMobil. Nothing in this document is intended to override or supersede the corporate separateness of local entities. Responsibility for local action and accountability remains with the local ExxonMobil-affiliate entities.