Knowledge Base

The objective of this page is to share basic knowledge about oils and greases.

žThis will benefit you by:

—Equipping you with basic need-to-know knowledge if you are in any way involved with Lubricants whether it be selling, advising or using/applying it.

Expertise. ?? What sort of experience and knowledge do we have in the room and what are the backgrounds of everyone?

Information Outline

žLesson 1 – —What is the function of oil and grease.

žLesson 2 – —Grades and specifications.

žLesson 3 – —Oil = Oil = Oil?

Function of Oils and Greases

  • žReduce friction between moving surfaces that are in contact
  • žReduce heating
  • žReduce wear and tear
  • žControl temperature
  • žControl corrosion
  • žAct as shock dampers (gears)
  • žRemove contaminants
  • žForms a seal (grease) to prevent ingress of dirt

Grades and Classifications (Oils)

We see many Grades, Specifications and Classifications on a variety of Products and it’s packaging, what are they and what does it mean?

  • ž“W”
  • žAPI
  • žSAE
  • žSABS / SANS
  • žISO
  • žEP
  • žViscosity Index (VI)
  • žMIL-L
  • žAdditives
  • žCF, CH, CI etc.
  • žSF, SJ, SL etc.
  • žGL-4 / GL-5
  • žHydraulic 46, 68 etc.
  • žI.G.O

Grades, Specifications Explained

ž“W”  –  (Winter)

In short, if you see an expression such as 10W-40, the oil is a multi-grade which simply   means that the oil falls into 2 viscosity grades, in this case 10W and 40.  This is made possible by the inclusion of a polymer, a component which slows down the rate of thinning as the oil warms up and slows down the rate of thickening as the oil cools down.  Multi-grades were first developed some 50 years ago to avoid the routine of using a thinner oil in winter and a thicker oil in summer.  For a 10w-40 to attain the specification target a 10W the oil must have a certain maximum viscosity at low temperature. The actual viscosity and the temperature vary with the viscosity grade but in all cases the lower the number, the thinner the oil. For example a 5W oil is thinner than a 10W oil at temperatures encountered in UK winter conditions.  This is important because a thinner oil will circulate faster on cold start, affording better engine protection and therefore lower long term wear!  For a 10w-40 to attain the other specification target a ?40? oil must fall within certain limits at 100°C.


  • žAPI  –  American Petroleum Institute
  • žSAE  –  Society of Automotive Engineers
  • žSABS  –  South African Bureau of Standards
  • žSANS  –  South African National Standards
  • žISO  –  International Standards Organization
  • žEP  –  Extreme Pressure
  • žGL  –  Gear Lube
  • žMIL-L  –  American Military Specification
  • žI.G.O  –  Industrial Gear Oil

žCF, CH, CI etc.

—C – Stands for Combustion. (Diesel Engines)

—The higher the letter in the alphabet next to C, the higher the quality and the latest technology applied.

žSF, SJ, SL etc.

—S – Stands for Spark. (Petrol Engines)

The higher the letter in the alphabet next to S, the higher the quality and the latest technology applied.

Most oils are combined Grades so it can be used in both Diesel and Petrol Engines e.g. CH/SJ

žGL  –  Gear Lube

—GL-4, GL-5 – Basically means the higher the number the more EP Additives are present. For use of Gear Oils the correct GL-Number should be selected. Higher in this case is not necessarily better.


—Viscosity is actually the Resistance of Oil to Flow. The higher the Viscosity the Higher the resistance to flow and vice-versa


—These are added to blended base oils to attain certain qualities that the final product needs to conform to.

—Types of additives are:

  • Viscosity Improvers
  • Detergents
  • Dispersants
  • Oxidation Inhibitors
  • Corrosion and Rust Inhibitors
  • Friction Modifiers
  • Anti-Wear Agents
  • Extreme Pressure Additives (EP)
  • Foam Depressants
  • Pour Point Depressants

žHydraulic Oils

—Although many manufactures of hydraulic fluid provide various grades of detergents and oxidation stability in the fluids they produce, the single factor that should weigh the heaviest in determining the best choice of fluid to use is viscosity. Viscosity is also most often expressed as the fluid’s ISO number or grade.

○ISO 32, 46, 68, 100, 150, 300.

○Higher Quality Versions will indicate this by AW (Anti-wear), OSO (Agip), HVI(High Viscosity Index), S etc.


—Oil derived from refining Crude Oil.


—Synthetic oil is a lubricant consisting of chemical compounds which are artificially made (synthesized) using chemically modified petroleum components rather than whole crude oil. Synthetic oil is used as a substitute for lubricant refined from petroleum when operating in extremes of temperature and load, because it generally provides superior mechanical and chemical properties to those found in traditional mineral oils.

Grease, Why Grease?

Greases are typically applied in areas where a continuous supply of oil cannot be retained, such as open bearings or gears.  Factors to be considered when selecting a suitable grease are operating temperatures, water resistance, oxidation stability etc. The second factor, not less important, are the grease’s characteristics, including viscosity and consistency.

žA lubricating grease consists of a base oil, performance additives and a thickener which forms a matrix that retains the oil in a semisolid state. Most grease thickeners are soaps, i.e. lithium, calcium, or aluminium soap. Complex soap greases have superior temperature resistance and are commonly usable up to 180ºC, at which the mineral oil vaporizes. A smaller number of greases, restricted to very special applications, are manufactured with non-soap thickeners such as organic-clays, poly-urea or silica (synthetic) compounds.

Oil = Oil = Oil?


Always make sure you choose the right oil with the correct specification for you or your customer’s application.

We have not even scraped the surface of what Lubrication is about

An Information Pack to supply more information and give more insight will be handed out.

It contains:

žContact Information

žMore Info on Grades and Specifications

žA Matrix of AGIP products, short descriptions and available pack sizes