• Large text
  • Medium text
  • Small text
  • text size

Mobiltherm Series 

Mobiltherm™ 600 Series

Heat transfer lubricants
Mobiltherm™ 600 Series heat transfer oils are high performance lubricants for use in closed and open, cold-oil sealed, indirect heating and cooling systems.

Resistant to thermal cracking
Formulated from base stocks that are resistant to thermal cracking and chemical oxidation, the oils provide efficient heat transfer and flash points will not significantly decrease at recommended operating temperatures.

Their viscosities are such that they can be pumped readily at both start-up and operating temperatures and they are capable of an extremely long service life without deposit formation or viscosity increase.

Benefits of Mobiltherm 600 Series include:

  • Marginal sludge and coke deposits resulting in lower maintenance
  • High heat transfer rates
  • Maximised operating efficiency
  • Long service life
  • Easy starting of cold systems

Download the Mobiltherm 600 series fact sheet >>


Mobiltherm oils are important members of the Mobil™ brand of specialty fluids that have gained a reputation for performance and reliability, even in severe applications. Modern refining techniques are a key factor in providing the excellent product features.

Mobiltherm™ 600 offer the following benefits:

FeaturesAdvantages and Potential Benefits
High resistance to thermal cracking and decompositionFree from sludge and coke deposits and minimum interference with heat transfer capability and minimized maintenance needs
Excellent thermal propertiesHigh heat transfer rates and improved operating efficiency and lower operating costs
Good thermal and oxidative stabilityLong trouble free service life and reduced downtime
Good low temperature fluidityEasy starting of cold systems

Application Considerations: Mobiltherm heat transfer oils should not be mixed with other oils since this may impair the excellent thermal and oxidation stability resulting in a change in other properties, and complicate analyses aimed at determining useful oil life. If the oils are used above their recommended maximum temperatures, vapor lock may result unless the system is designed to operate at the higher temperature by pressurizing with an inert gas such as nitrogen. At higher temperatures, fluid life will be shortened because the rate of thermal degradation which increases markedly as temperatures rise above the recommended limit. In well-designed systems the temperature of the oil film surrounding the heating element should be about 15ºC to 30ºC above the bulk oil temperature. If higher than this, the service life of the oil may be shortened and sludge and coke may be deposited which would interfere with the heat transfer rates.

As with other mineral oils, Mobiltherm heat transfer oils should be used only in systems with forced circulation. Systems that depend on convection for circulation of the heat transfer medium do not provide a rapid enough flow to prevent local overheating and rapid deterioration of the oil. Further, these oils are not recommended for use in open systems where hot oil is exposed directly to the air. If they spray or escape from leakage points, hot Mobiltherm oils may spontaneously ignite.

Mobiltherm 600 series can be used in open and closed installations where the bulk oil temperature ranges are as outlined in the table in the next tab.

  • Mobiltherm 603: Closed Systems (-15º C to 285º C), Open Systems (-15º C7 C to 150º C)
  • Mobiltherm 605: Closed Systems (-12º C to 315º C), Open Systems (-12º C to 180º C)
  • Mobiltherm 610: Open systems (-6°C to 250°C)
  • Mobiltherm 611: Open systems (-6°C to 275°C)
Mobiltherm 600 Series603605610611
Viscosity, ASTM D 445    
cSt @ 40ºC20.230.4113490
cSt @ 100ºC4.25.411.531.5
Pour Point, °C, ASTM D 97-15-12-6-6
Flash Point, °C, ASTM D 92194230250294
Density @15°C kg/l, ASTM D 12980.8350.8570.880.906