Product Description

Mobilgard™ 5100 by ExxonMobil is a premium quality, extra high performance, marine diesel engine cylinder oil. The outstanding performance of Mobilgard 5100 has been demonstrated at the elevated peak firing pressures and liner temperatures found in modern marine two stroke engines. It has an optimum viscosity of over 20 cSt. at 100ºC and low volatility to ensure excellent lubricant distribution and oil film retention. Through the use of unique synthetic thickener technology and a balanced formulation, the high viscosity and low volatility is attained with little or no use of bright stock which can create deposit formation due to poor thermal stability. Mobilgard 5100 has demonstrated outstanding ring and liner protection and cleanliness under sustained operation in highly corrosive engines that are under slow steaming conditions.

Features and Benefits

  • Excellent corrosion protection in newer, more demanding engine types during slow steaming operation.
  • Excellent thermal and oxidation stability can lead to reduced deposits and sludge formation. Cleaner engines can lead to reduced component wear rates.
  • Exceptional anti-wear properties lead to potentially reduced liner and ring wear and excellent anti-scuffing control.
  • Outstanding detergency capability leads to potentially cleaner pistons and liners and can help extend periods between overhauls.


  • Marine crosshead engines

Specifications and Approvals

Meets OEM requirements
MAN Diesel and Turbo* X
Wartsila/WinGD* X

*Please follow all OEM guidelines for engine model, feed rate and fuel sulfur use

Typical Properties

SAE Grade 50
Specific Gravity at 15ºC 0.953
Flash Point, ºC, ASTM D 92 244
Pour Point, ºC, ASTM D 97 -24
Viscosity, ASTM D 445
cSt, at 40 ºC 242
cSt, at 100 ºC 21.1
Viscosity Index, ASTM D 2270 103
TBN, mg KOH/g, ASTM D 2896 100

Health and Safety

Based on available information, this product is not expected to produce adverse effects on health when used for the intended application, following the recommendations provided in the Material Safety Data Sheet (MSDS). MSDSs are available upon request through your sales contract office, or via the Internet on This product should not be used for purposes other than its intended use. If disposing of used product, take care to protect the environment.


It cannot be guaranteed that the product information given above is up to date. For the latest version of the Product Data Sheet we refer to the product library of ExxonMobil.