Mobilgard™ 300 C

ExxonMobil marine , Ireland

Two-Stroke Diesel Engine System Oil

Product Description

Mobilgard™ 300 C is a premium quality system oil specially formulated to provide superior engine cleanliness, better wear protection and longer oil life when compared with conventional system oils. It is designed for use in two-stroke, crosshead marine diesel engines operating under severe conditions. This product has sufficient alkalinity to protect against strong acids which may find their way into the crankcase from the combustion of fuel sulphur, and it has enhanced load carrying ability in order to reduce wear in heavily loaded bearings and gears.


Features and Benefits

The high quality paraffinic base oils used in Mobilgard 300 C have excellent thermal stability and oxidation resistance. The formulation includes proprietary detergent and anti-wear additive systems to deliver enhanced crankcase cleanliness, along with excellent protection for highly-loaded engine parts. Mobilgard 300 C also provides good rust protection in case of water contamination, and excellent water separation characteristics.

When used as recommended in crosshead type diesel engines, Mobilgard 300 C system oil offers the following features and potential benefits:



Advantages and Potential Benefits

Enhanced detergency and improved thermal and oxidation stability

Reduced deposits in piston cooling spaces

Better piston cooling efficiency

Cleaner crankcases and circulation tanks

Enhanced load-carrying and anti-wear performance

Excellent protection for highly loaded engine components such as bearings and gears

Excellent rust and corrosion properties

Longer bearing life

Protects critical bearing surfaces

Good water tolerance and separation capability

Effective lubrication in the presence of water

Longer oil life due to efficient water separation



Mobilgard 300 C is recommended primarily for use as system oil in late model, high-output, crosshead diesel engines, especially those engines employing the system oil for piston cooling. It will prevent or reduce deposit formation in the piston cooling spaces, thus maintaining piston cooling efficiency and reducing the incidence of piston top burning and piston crown cracking. It will also prevent or reduce crankcase deposits and will provide outstanding protection for heavily loaded bearings and gears. Good rust prevention and water separation characteristics make Mobilgard 300 C an excellent system oil in older design crosshead diesel engines which have water-cooled pistons and where crankcase deposits can be a problem with lower-quality system oils.


Properties and Specifications



SAE 30

Ash, Sulfated, wt%, ASTM D874


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


FZG Scuffing, Fail Load Stage, A/8.3/90, ISO 14635-1


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


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


Pour Point, °C, ASTM D97


Specific Gravity, 15.6 C/15.6 C, ASTM D4052


Total Base Number, mgKOH/g, ASTM D2896


Viscosity Index, ASTM D2270



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.


ExxonMobil Marine Limited
Ermyn Way
Leatherhead, Surrey
United Kingdom KT22 8UX

Due to continual product research and development, the information contained herein is subject to change without notification.  Typical Properties may vary slightly.