El Mar®Ashless Heavy Duty GEO

Ashless Natural Gas Engine Oil

Phillips 66®El Mar Ashless Heavy Duty GEO is a high quality, ashless gas engine oil designed for use in naturally aspirated and moderately turbocharged 2-stroke cycle natural gas engines. Engines operating in this type of service typically are found on crude oil and gas transmission pipelines, electrical power generators, gas compressors, irrigation water pumps and well drilling rigs.

Features & Benefits

  • Field-proven performance in providing outstanding engine cleanliness
  • Ashless formulation helps minimize port deposits
  • Good dispersancy protects against sludge and varnish formation
  • Excellent resistance to oxidation and nitration
  • Protects against scuffing and wear
  • Protects against rust and corrosion
  • Does not contain any bright stock, which can cause harmful carbon deposits


  • 2-stroke cycle and some 4-stroke cycle natural gas engines where the manufacturer specifies an ashless gas engine oil
  • SAE 5W-30 special application only contact technical service

Technical Details

Licenses & Approvals

El Mar Ashless Heavy Duty GEO is recommended for use in natural gas engines manufactured by:

  • Ajax
  • Climax
  • Colt-Fairbanks Morse
  • Cooper Bessemer
  • Dresser Clark
  • Dresser Rand (Category I & II)
  • Worthington
Additional Details
SAE Grade5W-30
Specific Gravity @ 60°F0.8586
Density, lbs/gal @ 60°F7.15
Color, ASTM D15003
Flash Point (COC), °C (°F)214(418)
Pour Point, °C (°F)-42(-44)
Viscosity, Kinematic
cSt @ 40°C61
cSt @ 100°C10.45
Viscosity Index161
Cold Cranking Viscosity, cP @(°C)5150(-30)
Sulfated Ash, ASTM D874, wt %<0.01
Total Base Number (TBN), ASTM D28961
Phosphorus, wt %0.54