Silver bearings outside case

Mobil Rarus™ 400 Series

Get longer running periods between maintenance intervals with Mobil Rarus™ 400 Series air compressor oils.

Our Mobil Rarus™ 400 Series ashless air compressor oils are designed for compressor systems employing gears and bearings, and are highly recommended for crankcases. They are formulated with high-quality mineral base oils and a high-performance additive system to provide exceptional equipment protection and reliability for compressors operating under mild to severe conditions. 

Mobil Rarus 400 Series air compressor oils can result in cleaner compressors and lower deposits compared to conventional mineral oils, resulting in: 

  • Longer running periods between maintenance intervals
  • Improved valve performance
  • Lower maintenance costs

Download PDS Talk to an expert Send to a colleague Find a distributor

Mobil Rarus™ 400 Series offers 5 lubricant grades

Narrow your results by using the filters below

There are no results '{{filters.q}}'.

Showing {{results.length}} of {{totalCount}} product grades


Technical resources

Air compressor maintenance

Cut the cost of compressing air in your plant by taking basic steps toward making your system more efficient.

Technical topics, PDF

All resources

Features and Benefits

The use of the Mobil Rarus 400 Series oils can result in cleaner compressors and lower deposits compared to conventional mineral oils, resulting in longer running periods between maintenance intervals. Their excellent oxidation and thermal stability safely allow extended life capability while controlling sludge and deposit formation. They possess outstanding anti-wear and corrosion protection, which enhances equipment life and performance.

FeaturesAdvantages and Potential Benefits
Low Ash and Carbon FormationImproved valve performance
Reduced deposits in discharge lines
Reduced potential for fires and explosions in discharge systems
Improved compressor performance
Outstanding Oxidation and Thermal StabilityLonger oil life
Improved filter life
Lower maintenance costs
High Load-carrying abilityReduced wear of rings, cylinders, bearings and gears
Excellent Water SeparabilityLess carryover to downstream equipment
Reduced sludge formation in crankcases and discharge lines
Reduced blockage of coalescers
Less potential for emulsion formation
Effective Rust and Corrosion ProtectionImproved protection of valves and reduced wear of rings and cylinders



The Mobil Rarus 400 Series oils are recommended for single and multistage air compressors. They are particularly effective for continuous high temperature operation. The maximum compressed air temperature, according to DIN 51506, is 220 °C. They are suitable for reciprocating and rotary type machines with the lower viscosity grades mainly used in rotary compressors. Rarus 400 Series oils are recommended for units with a history of excess oil degradation, poor valve performance or deposit formation. They are compatible with all metals used in compressor construction and with mineral-oil compatible elastomers used in seals, O-rings and gaskets.

Mobil Rarus 400 Series oils are not intended or recommended for use in air compressors for breathing applications.

The following types of compressors have shown excellent performance with the Mobil Rarus 400 Series oils:

  • Reciprocating air compressor crankcases and cylinders
  • Rotary screw compressors
  • Rotary vane compressors
  • Axial and centrifugal compressors
  • Compressor systems with critical gears and bearings
  • Compressors used in stationary and mobile applications


Specifications and Approvals

Mobil Rarus 400 Series meets or exceeds the requirements of:424425426427429
DIN 51506 VD-L (1985-09)XXXXX


Typical Properties

Mobil Rarus 400 Series424425426427429
ISO Viscosity Grade324668100150
Viscosity, ASTM D 445     
cSt @ 40º C324668104.6147.3
cSt @ 100º C5.46.98.911.614.7
Viscosity Index, ASTM D 2270105105105100100
Sulfated Ash, wt%, ASTM D 874‹0.01‹0.01‹0.01‹0.01‹0.01
Copper Strip Corrosion, ASTM D130, 3 h @ 100º C1B1B1A1B1A
FZG Load Support, DIN 51354, Fail Stage1211121111
Rust Characteristics; ASTM D665 B; ASTM D665 APassPassPassPassPass
Foam Seq I, ASTM D 89210/020/00/030/0430/20
Flash Point, ºC, ASTM D 92236238251264269
Density @ 15º C, ASTM D 12980.8660.8730.8770.8790.866


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.