Mobil GEO™ 15W-40

Premium Natural Gas Engine Oil

Mobil GEO™ 15W-40 is a premium fleet engine oil specifically formulated to provide reliable protection for trucks and buses using Compressed Natural Gas (CNG) or Liquefied Natural Gas (LNG). Mobil GEO 15W-40 is formulated from high quality base stocks and a balanced additive system. This advanced medium ash formulation provides excellent oxidation, nitration, and thermal stability to minimize combustion chamber ash deposits. Mobil GEO 15W-40 lubricates with less varnish, sludge, and carbon build-up under the most severe operating conditions.

Equipment lubricant recommendations

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Data sheets

Features and Benefits

Modern high output, high speed, lean-burn diesel type engines using natural gas fuels place severe demands on engine lubricants. Mobil GEO 15W-40 is formulated to strict standards to deliver reliable engine performance in modern diesel type engines using natural gas as the primary fuel. The key benefits include:

  • High thermal and oxidation stability helps control sludge build-up and deposits
  • Reserve TBN neutralizes oxy acids and nitrates to reduce deposits
  • Shear stability reduces oil consumption and provides bearing wear and cylinder liner scuff protection
  • Effective detergency/dispersancy keeps engines cleaner
  • Low levels of Zinc and Phosphorous help extend catalytic converter life


    Recommended by Imperial Oil for use in:

  • Spark ignited CNG and LNG-fueled lean-burn engines
  • Dual fuel engines using diesel fuel for start-up and 15% diesel pilot fuel with CNG/LNG
  • On-highway light and heavy-duty trucks and busses

Specifications and Approvals

Mobil GEO 15W-40 is recommended by Imperial Oil for use in applications requiring:
Detroit 7SE272 9510


Typical Properties

Mobil GEO 15W-40  
SAE Grade 15W-40
Viscosity, ASTM D 445  
cSt @ 40ºC 100
cSt @ 100ºC 14.4
Viscosity Index, ASTM D 2270 130
Sulfated Ash, wt%, ASTM D 874 0.5
Total Base #, mg KOH/g, ASTM D 2896 5.0
Pour Point, ºC, ASTM D 97 -27
Flash Point, ºC, ASTM D 92 215
Density @ 15ºC kg/l, ASTM D 4052 0.88


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.