Everything You Need To Know About Engine Oil

A car engine is a complex piece of machinery which operates under a wide range of temperatures, as such you need to ensure that you fill it with the correct engine oil to lubricate and protect all the moving parts from wear and corrosion, as well as the build-up of dirt and harmful deposits.

Here we answer the most common FAQs about engine oil.

What Does The Combination of Numbers and Letters on a Bottle of Oil Actually Mean?

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The number rating for engine oil is all about the SAE viscosity rating at different temperatures. As an example we’ll use 5W-30 oil.

The 5 is the viscosity rating when it is cold, the ‘W’ stands for Winter and 30 is the viscosity rating when then engine is at operating temperature. This is usually around 100ºC (212ºF).

Engine oils thin as they heat up, multi grade engine oils thin less when the engine reaches its full temperature allowing the engine to maintain a constant oil pressure.

Why Do I Need To Change My Engine Oil?

As an engine burns fuel it degrades the oil within the engine. Regularly changing the oil in your engine helps to remove harmful contaminates and it replenishes the additives which have been depleted.

What Is Engine Oil Made Of?

Engine oils vary from manufacturer to manufacturer, but generally an engine oil will be made up of between 75-90% base oil. The remaining 10-25% is made up of additives which help to maintain the oil’s viscosity at high temperatures.

The base oil determines the fundamental properties of the engine oil and the additives help to enhance the base oil as well as helping to maintain the base oil and the engine components.

Should I Use After-Market Engine Oil Additives?

No – manufacturers spend a lot of time in research and development creating the perfect balance of oil and additives. This means that you shouldn’t use any additional oil additives in your engine.

What Is The Difference Between Conventional and Synthetic Engine Oil?

The base oil within any engine oil is either conventional or synthetic. If the base oil is conventional this means it has only been refined from crude oil. If the base oil is synthetic, it means that the oil has gone through an additional chemical engineering process. The additional process gives the oil better properties, such as more uniform oil molecules which create better lubrication, resulting in better engine performance.

Is Synthetic Oil Compatible With Conventional Oil? Can The Two Types Be Mixed?

Engine oil labelled as synthetic already has conventional engine oil as part of its formulation, in the base oil. Manufacturers are also careful to test engine oils to make sure they are compatible with other brands. This means that as long as you use oils of the same SAE viscosity rating you can mix engine oils from different manufacturers.

However, we recommend sticking to one type and not mixing engine oils.

Can You Use Synthetic Engine Oil To ‘Break-In’ An Engine?

Yes you can. In fact the majority of vehicles manufactured today are factory filled with synthetic engine oil. Many racing teams also use synthetic oil to break-in their engines. If it’s good enough for a race team, it’s good enough for your daily runabout.

Can You Use Synthetic Oil In Any Vehicle?

Yes – it doesn’t matter whether you have an old or new car, the engine has high mileage or is a performance vehicle, you can use synthetic oil in any vehicle.

What Is Engine Sludge and What Causes It?

Every time you use your car’s engine, by-products from combustion build up and contaminate the engine’s oil. Over time the contaminants build up and can settle in the engine oil forming a ‘sludge’ in the bottom of the engine. Using low quality oils, not regularly changing your engine oil, or infrequent engine maintenance can all lead to sludge forming inside your engine.

Why Should I Use The Oil Grade That The Manufacturer Recommends For My Car?

Every engine is designed to use a particular oil viscosity in order to lubricate the engine components properly. Using oil which is too thin can cause wear issues within the engine. Using oil which is too thick can lead to the engine having to work harder and becoming less efficient.

We always recommend that you refer to your vehicles owner’s manual to find the manufacturers recommended SAE viscosity for use in your particular engine.

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