Fully & Semi Synthetic Motor Oils

Motor oil, or engine oil, whether fully or semi synthetic, is used to provide the necessary lubrication for the internal combustion engine. While it's main function is to lubricate moving parts, motor oil also cleans, inhibits corrosion, improves sealing, and cools the engine by carrying heat away from moving parts.

Motor oils are themselves derived from petroleum based and non petroleum synthesized chemical compounds. The motor oils today are mostly blended using base oils composed of hydrocarbons, polyalphaolefins (PAO), and polyinternal olefins[2] (PIO).

Motor Oil Grades for 4 Stoke Engines

The Society of Automotive Engineers (SAE) has established a numerical code system for grading motor oils according to their viscosity characteristics.

This SAE viscosity grading's runs from low to high viscosity: 0, 5, 10, 15, 20, 25, 30, 40, 50 or 60.

The numbers 0, 5, 10, 15 and 25 are also suffixed with the letter W, designating their "winter" or cold-start viscosity.

Thus the number 20 comes with or without a W, depending on whether it is being used to denote its cold or hot viscosity grade.

It is also worthy to note that the SAE has a separate viscosity rating system for gear, axle, and manual transmission oils. These should not be confused with engine oil viscosity, the higher numbers of a gear oil (e.g. 75W-140) do not mean that it has higher viscosity than an engine oil.

Single Grade Motor Oils

A single-grade engine oil, as defined by SAE J300, does not use a polymeric Viscosity Index Improver additive. There are eleven viscosity grades, of which six are considered Winter-grades and given a W designation.

These 11 viscosity grades are 0W, 5W, 10W, 15W, 20W, 25W, 20, 30, 40, 50, and 60, These numbers referring to the 'weight' of a motor oil.

For some applications which do not have a wide temperature range, single-grade motor oil is most satisfactory. Examples of applications being lawn mowers, some industrial applications, and vintage / classic cars.

Multi Grade Motor Oils

The temperature range motor oils are exposed to can be wide, ranging from the cold temperatures experienced in the winter before the vehicle is started, to the hot operating temperatures when the vehicle is fully warmed up in hot summer weather or climates.

Each oil will have a high viscosity when cold and a lower viscosity as it gets warmer, this being the engine's operating temperature. The difference in viscosities for most single-grade oil is too large, so to bring the difference in viscosities closer together to a level that can be achieved, special polymer additives called viscosity index improvers (also known as 'VIIs') are added to the oil.

Once added, the additives turn the oil into a 'multi-grade motor oil'. The idea is to produce an oil that will have the viscosity of the base grade when cold and the viscosity of the second grade when hot.

This enables one type of oil to be used all year rather than having to use one in the winter and another in the summer.

Exol Range of Multigrade Oils


Our range covers most if not all of the viscosity types you will need, a list of some being shown below:-
  • 10w 40 synthetic motor oils
  • 10w 40 semi synthetic oils
  • 5w 20 oil
  • 5w 40
  • 5w 50
  • 5w 30 longlife
  • 75w 90 gear oils
  • performance Motor Oils
  • Racing Oils

Manufacturers Covered

  • BMW
  • VW
  • Vauxhall
  • Ford
  • Mercedes
  • Skoda
  • Honda
  • and many more

Automotive Products

  • Brake Fluids
  • Power Steering Fluids
  • Automatic Transmission Fluid
  • and much more

exol have a reputation for the highest quality products, flexible service, and fast delivery our outstanding technical support teams are there to help you choose the right oils / lubricants / cleaners and greases for every application.

Our research and development team have also developed motor oils designed to extend oil life as far as is possible.

Whatever your needs, our specialist team are there to assist, and if the right type of product is not available now, we can develop one (subject to quantities of course).