Which Oil Should I use for my Car?

A lot of drivers will find choosing the right oil for their car confusing and this poses the question which oil for my car? There have been major advancements in the types of car oils produced in recent years. Choosing the right oil for your car can mean that your car will last longer before it needs any major work so it could be essential that you choose the right one. Modern car oils are made to keep the engine clean and protect it from corrosion and sludge formation. Sixt has provided some tips below for you to look out for when you are deciding which oil for my car.


Oil Viscosity

Engine oils are graded by their viscosity, which is to do with their thickness. The viscosity changes with temperature.


Modern oils have a lower viscosity, making them thinner. By having lower viscosity it means that the engine will turnover more easily and the oil can circulate around the engine quickly after it’s started up.


Oil has to operate in varying temperatures from the cold winter weather to hot summer conditions. Because of this oils contain additives that change the viscosity so that it can have a different viscosity when it’s cold and another for when it’s hot. These are known as grades and will be marked clearly on the container. The first lower number will be for cold temperatures and the second higher number will be for hot temperatures. Check your car handbook to find out what is suitable for your car.


Oil Specifications

All car engines are different and therefore all car oils are different too. Now oil companies and car manufacturers’ work together to perform a number of tests specific to oil so that they are compatible with the latest engines.


There are a different set of standards for car oil around the world. In the UK containers for oil will usually have specifications from the CCMC/ACEA (European Constructors). Others to look out for are The American Petroleum Institute (API), ILSAC (The International Lubricant Standardization and Approval Committee) or JATO (the Japanese Automotive Standards Organization). Generally, newer oils will work in older cars but not the other way round. But some new oils will not work in older cars, especially fuel economy oils.


Some manufacturers have developed their own oils that are specific to their own cars. These are oils made to last and help to keep the engines running for longer without being serviced. 

CCMC/ACEA (European Constructors) Specifications

Below is a list of some ACEA specifications.


  • A1 Fuel economy petrol
  • A2 Standard performance level
  • A3 High performance and/or extended drain
  • A5 Fuel economy petrol with extended drain capability
  • B1 Fuel economy diesel
  • B2 Standard performance level
  • B3 High performance and/or extended drain
  • B4 For direct injection passenger car diesel engines
  • B5 Fuel economy diesel with extended drain capability Heavy-duty diesel
  • E1 Non-turbo charged light duty diesel
  • E2 Standard performance level
  • E3 High performance and extended drain
  • E5 High performance and extended drain including some API specs
  • E6 Euro 4 engines – low SAPS (sulphated ash, phosphorous, sulphur) for vehicles with DPF
  • E7 Euro 4 engines – exhaust after treatment /exhaust gas recirculation


Ensure that you check the vehicle Handbook

Because there are so many different types of oil available to use its important that you check your vehicle handbook so that you have the right one for your car. ACEA/API specifications should be marked clearly on the label.


Everybody at Sixt hopes that this guide has helped our customers out so that they no longer need to ask which oil for my car?


* Please note: All information was correct at the time of publication.