Knowledge Centre

Engine Oil

Oils are made from base stocks (which make up and can represent up to 90% of the product) and additives. Some base stocks are made from petroleum while some are synthetically made by chemists.

There are 5 groups of base stocks: the lower the group number, the more petroleum they contain and the less refined they are. The higher the group number, the more synthetic the oil composition will be


There are multiple factors within oil, each oil will come under a specific oil approval for certain engines, the main differences are the thicknesses. I.e. a 5W30 will be thinner than a 10W40, the first number is the thickness of the oil when cold (Cold Crank viscosity) and the second number is when the oil is up to temperature.


Mineral Oil - is made from refined crude petroleum and is ideal for older vehicles.

Synthetic Oil - chemically modified with fewer impurities. 

Semi Synthetic Oil - a mixture between mineral oil and synthetic oil.

Engine oil products kept at suitable non extreme temperatures and left un-opened/sealed can last for 10 years. Once a product has been opened it should be used within about 2 years.

If there are deposits on the bottom of the container the oil will have to be replaced as these cannot be dissolved by shaking the container. Oil should be disposed of responsibly by taking it to your local recycling centre.


By using manufacturer approved oils you adhere to any factory specifications and requirements resulting in increased reliability, optimum performance and fuel efficiency.

Approved oil also undergoes vigorous testing and conditions which could also contribute to added protection and reduced maintenance costs.

When servicing a vehicle, adhering to the manufacturers recommendations will help to keep the vehicle in warranty.



  • Read horizontally across.
  • Assumes 96 VI single grade oils.
  • Equivalence is in terms of viscosity at 40°C only.
  • Viscosity limits are approximate: For precise data, consult ISO, AGMA and SAE specifications.
  • W grades are represented only in terms of approximate 40°C viscosity. For low temperature limits, consult SAE specifications.


The difference between API GL-4 and GL-5 gear oils is the amount of EP additives. Sulphur/Phosphorus containing products are used as EP-additive.

The additive has the purpose to prevent the occurrence of micro-welds on the gear flanks at the local high temperatures which prevail in EP circumstances GL-5 has roughly twice the amount of EP additives compared to GL-4, which is why it is often used in high-pressure circumstances such as in a front axle and rear axle differential.

Sulphur/Phosphorus additives however have an unfavourable property: they can react aggressively towards bronze and copper. This can be disastrous for the synchromesh rings of a gearbox. Therefore it is not recommended to use GL-5 in a gearbox unless the manufacturer allows this.

To conclude:

  • GL-4 is suitable for hypoid gear service when they are under severe service but are without shock loading.

  • GL-5 is suitable for hypoid gear service under severe service and shock loads and not for use in a gearbox.

  • These are usually shown as 'API GL-4' which stands for 'American Petroleum Institute' - The largest US trade association for the oil and natural gas industry.


  • Recommended storage time for lubricant oils and lithium-based greases – 12 months
  • Store inside or undercover and avoid storing in extreme temperatures
  • Drum bungs should always be sealed and tight when not in use
  • Keep away from potential contamination (dust etc.)


Storing metal barrels / drums

When it rains, the water creates a small pool on top of the barrel and the bungs can become submerged in water. When the barrel heats and cools, it breathes which can result in water entering the barrel. This can happen to barrels that have not been opened yet too.

Once the water is in the oil it will begin to separate and sit at the bottom of the barrel, so using a barrel pump which will pump directly from the bottom of the barrel, will inevitably result in damaging the vehicle or machinery with water contaminated oil.

The best way to mitigate the risk of this happening is by storing barrels inside or undercover. However, when storing outside is unavoidable, another simple and inexpensive solution is to place a small block under one edge of the barrel, so it leans slightly to the side and ensure the bungs are at 3 and 9 o’clock positions. This will allow the water to drain off the barrel and not be sucked in as the barrel breathes.

For best results in maximising the life of a lubricant is to keep it clean, dry and cool. See below a table highlighting variables that influence storage life of new lubricants.



Maximise storage life

Minimise storage life

Storage temperature



Temperature variability




Plastic containers / drums

Poorly conditioned metal drums




Outdoor storage





Commercial Vehicles:
Usage for commercial vehicles will depend on tonnage of the vehicle – rates usually range from 3-6% of diesel consumption.

AdBlue consumption guide for commercial vehicles

Passenger Cars: 
Passenger cars will typically use around 1 litre of AdBlue every 350 to 600 miles. AdBlue is usually around 3-6% of diesel consumption.

The amount that your car requires depends on engine size, how you drive and the size of the AdBlue tank. Check your cars manual for a specific answer on how much AdBlue your car takes.

Machinery & Plant:
For diesel powered machinery and off-road vehicles, this varies due to a wide range of factors, including engine size, usage and operating conditions.

Bus and Coach:
Bus consumption of AdBlue usually equates to around 5% of diesel consumption. However, this is dependent on the mileage of the vehicle – city buses will typically use 20-30 litres each month, compared to 40 litres per month for buses operating over longer, cross-country routes.


If you’re driving and the car runs out of AdBlue, the power and engine performance will be limited in functionality as Limp Home Mode (which is a safety feature mechanism which stops the car overheating) will be activated. Once the car’s engine is stopped, it won’t re-start until the tank containing AdBlue is refilled.



Base oil - makes up the majority of the weight of any grease. This can vary greatly depending on product and application but is generally 75-90% base oil which is non-solid and can be mineral or synthetic. These vary greatly on viscosity to accommodate different applications.

Thickener – makes up a much smaller part of the grease, however the thickener holds the oil together with the most common being lithium & lithium complex, effectively acting like a sponge that holds any base oils and additives. Different amounts of thickeners are used to get to different NLGI grades (NLGI 000 through to NLGI 6), however the vast majority of grease used is between NLGI 00 and NLGI 2. ‍

Additives – make up a small percentage of the total weight of the grease however greatly affect the properties of grease. Additives are selected grease by grease to suit the application. Additives packages improve a grease and increase machinery life, through:
• Protection against corrosion and oxidation
• Friction reduction

Before selecting a grease, it is important to identify what your machinery needs, which can vary depending on:

Operating temperature - Different greases can withstand varying temperature ranges. Greases are designed to release small amounts of oil at certain temperatures to keep parts lubricated, too higher temperature the oil will escape, too low and the grease will not release enough oil to lubricate effectively.

‍‍RPM or angular velocity of moving parts – greases have varying tacky properties (stickiness) applications with parts that spin very quickly tend to fling off any grease with a thinner base oil. Where parts are moving very quickly a grease with a thicker base oil is recommended. Slower moving applications generally have a thinner base oil however other factors such as the load and vibration need to be considered alongside temperature.

Benefits of selecting the right grease:

  • Reduced breakdowns and bearing failures
  • Reduced downtime of machinery
  • Reduced amount of grease required if correct product used
  • Increased grease life, reducing the time spent re-greasing