Mobil Rarus™ 424J

Mobil industrial , South Korea

Air Compressor Lubricant

Product Description

The Mobil Rarus™ 424J is the premium performance air compressor lubricant primarily intended for the lubrication of severe duty rotary screw and vane air compressors. The product is formulated with specific high quality mineral base-oils and a high performance additive system designed to provide exceptional equipment protection and reliability for compressors operating under severe conditions. Mobil Rarus 424J provides excellent wear protection and outstanding resistance to oxidation and thermal degradation. Its exceptional water separating characteristics reduce problems with emulsion formation and carryover into downstream piping and equipment. The product is designed to meet the stringent requirements of the major compressor manufacturers.


Features and Benefits

The use of the Mobil Rarus 424J oil 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.



Advantages and Potential Benefits

Reduce Vanish and Sludge Formation

Improved valve performance

Reduced deposits in discharge lines

Reduced potential for fires and explosions in discharge systems

Improved compressor performance

Outstanding Oxidation and Thermal Stability

Longer oil life

Improved filter life

Lower maintenance costs

Excellent Water Separability

Less 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 Protection

Improved protection of internal compressor components



The Mobil Rarus 424J oil is primarily for rotary screw and vane air compressor, very effective in screw type compressors with oil injection cooling; compressors with a history of excess oil degradation, poor valve performance or deposit formation. It is particularly effective for continuous high temperature operation. The maximum compressed air temperature, according to DIN 51506, is 220°C.. The product is compatible with all metals used in compressor construction and with mineral-oil compatible elastomers used in seals, O-rings and gaskets.


Mobil Rarus 424J oil is 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 424J oil:

     •  Rotary screw compressors

     •  Rotary vane compressors

     •  Compressor systems with critical gears and bearings

     •  Compressors used in stationary and mobile applications


Properties and Specifications



ISO 32

Copper Strip Corrosion, 3 h, 100 C, Rating, ASTM D130


Density @ 15 C, kg/l, ASTM D4052


Emulsion, Time to 0 mL Emulsion, 54 C, min, ASTM D1401


Flash Point, Cleveland Open Cup, °C, ASTM D92


Foam, Sequence I, Tendency, ml, ASTM D892


Kinematic Viscosity @ 100 C, mm2/s, ASTM D445


Kinematic Viscosity @ 40 C, mm2/s, ASTM D445


Pour Point, °C, ASTM D97


Rotating Pressure Vessel Oxidation Test, min, ASTM D2272


Rust Characteristics, Procedure B, ASTM D665


Viscosity Index, ASTM D2270


Foam, Sequence I, Stability, ml, ASTM D892



Health and safety

Health and Safety recommendations for this product can be found on the Material Safety Data Sheet (MSDS) @

All trademarks used herein are trademarks or registered trademarks of Exxon Mobil Corporation or one of its subsidiaries unless indicated otherwise.


Mobil Korea Lube Oil Inc.

Level 22, Seoul Square bd., Hangang-daero, Jung-gu, Seoul, Korea


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
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