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Engine Oil

Engine oil explained

With an ever increasing range of vehicles available, maintaining these valuable business assets is increasingly important to your bottom line. Any internal combustion powered vehicle will need a regular oil change to maintain efficiency and output, and prolong engine life. Engine oil is, in its simplest terms, a lubricant that reduces wear on essential parts of a vehicle’s engine. However, we all know that engine oil performs far beyond this, and is a vital component for any commercial business relying on the smooth running of vehicles and transport solutions.

What is engine oil?

Engine oil is a combination of base oil and a range of performance enhancing additives like dispersants, detergents and viscosity improvers. In general, there are three types of engine oil; mineral, semi-synthetic and fully synthetic.


The least refined form of engine oil and often the least expensive, mineral oil is generally used only at the manufacturer’s request as it contains the least additives.


The midpoint between a mineral oil and full synthetic, semi-synthetic engine oil has been modified to improve performance yet still offers a competitive price point.

Fully synthetic

The most premium engine oil, fully synthetic oils have been designed and modified to produce maximum results. Whilst they are more expensive, they offer advanced benefits for enhanced performance.

Viscosity ratings

As well as the molecular structure, as noted above, when choosing an engine oil you will need to consider the viscosity rating. Viscosity ratings exist to advise users on how easily an oil pours in certain temperatures. As engine oils have advanced, engine oil additives have allowed standard oil to be manipulated into producing the viscosity needed for specific applications. 

Cold temperature performance: For vehicles operating in winter or in colder regions, a low winter viscosity engine oil will produce optimum engine results. A low winter grade means that the oil thickens less in cold temperatures and will therefore run more easily through your engine

Warm temperature performance: High temperatures can cause some engine oils to become too thin too quickly, compromising overall performance. Using an engine oil with a high viscosity will reduce this problem.

Whilst some mineral oils do offer protection from varying temperatures, fully synthetic oils offer a far more tailored solution with a host of additives to manage the impacts of seasonal weather conditions. 

Who uses engine oil?

A myriad of businesses are reliant on commercial vehicles, from cars and motorcycles to Light Commercial Vehicles (LCV) and Heavy Goods Vehicles (HGV). Many sectors can benefit from the performance enhancing capabilities of engine oil.

  • Couriers
  • Private garages
  • Motorsport
  • Private hire firms

A regular part of your routine

Regularly changing the oil filter and engine oil is a straightforward yet essential task to get the most from your engine oil and, ultimately, from your vehicle. How long engine oil lasts will depend on the frequency of use and the overall output of your vehicles. For modern vehicles, it can be anywhere from 10,000 miles up to 24,000 miles. Truck engine oil is likely to need changing after around 70,000 to 80,000 miles. It’s always worth checking your engine oil level regularly and topping up as necessary. For large fleets of commercial cars or lorries, or for performance reliant vehicles, maintaining engine oil levels and using the right engine oil can keep you one step ahead of the competition.

Buying engine oil

Certas Energy Lubricants sells an extensive range of engine oils from leading manufacturers like Castrol, Shell, Valvoline and Q8Oils. If you’re looking to purchase engine oil for commercial and business use, you can browse our catalogue or call us on 0345 266 6055. We distribute in small and large quantities and offer full technical support to help you choose the right engine oil for your specific business and vehicle function.

When buying engine oil, the biggest things to consider are:

  • Whether a fully synthetic, semi synthetic or a mineral oil is required
  • The correct viscosity 
  • The engine oil grade required 
  • The car or truck manufacturer’s specification, which can usually be found in the operating manual
Castrol Service lubricants advisor UK

Our partners

We are partnered with leading global engine oil suppliers. Each manufacturer can guide and advise you on which oil in their extensive portfolio will best suit your needs. You can find details and information on our partner pages or go straight to the engine oil checkers for each brand.

Engine Oil FAQs

Engine oil comprises a base oil, generally distilled crude oil,  which then has a series of additives mixed in during the production process. These additives contribute to the engine oil’s capabilities. Mineral, semi synthetic and fully synthetic oils all have many additives including detergents, dispersants and viscosity index improvers. The final blend of additives is what manufacturers use to determine the engine oil grade and specification.

Engine oil performs several key functions. Primarily, it reduces friction of the engine parts to minimise wear and tear over time. Additionally, engine oil can help to regulate the temperature of the engine, while dispersant additives keep soot in suspension and detergents maintain the cleanliness of the engine.

You can find help choosing the right engine oil by using the manufacturer’s handbook for the vehicle or truck you are using. You will also find lubricant selectors on premium manufacturers’ websites such as Shell, Valvoline and Castrol.

Premium approved manufacturer engine oil  has been tested to last for the planned drain interval. Commercial vehicles check and change the engine oil at regular intervals to help prolong the lifespan of engines and reduce long term repair costs.

Choosing the right engine oil for the right job ensures the engine will perform exactly as the manufacturer intended it to and will protect the engine for maximum performance and longevity. Therefore, getting the best price means paying for a product that offers long term cost savings. Some engine oils may seem cheaper initially but will result in reduced output over the life of the engine, ultimately costing more in repairs or even replacements.

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