What is the Best Engine Oil for My Car?

Protecting your car’s engine starts with using the right type of oil. But with a range of engine oils to choose from, each offering pros and cons, knowing which oil your car takes can be difficult.

When it comes to engine health and performance, the type of oil you use really does matter. Engine oil lubricates moving parts, reduces corrosion, and helps to prevent premature wear and tear. So, if you use the wrong oil in your car, you might not achieve the level of protection your engine needs.

Not sure what oil your car takes? Our car oil checker helps you find compatible engine oil with your reg number. So, whether you drive an Audi or a Toyota, you can find the oil for your car in a few simple steps.

Want to learn more about different engine oils? Read our essential guide to buying oil for your car below.

Anyone who’s ever looked at engine oil will know just how confusing choosing the right product can be. With lots of different grades and options, finding the right one for your car can be tricky.

In this guide, we’ll take a look at the different oil grades and what they mean, as well as some of the other points to consider when buying oil for your car.

Refueling and pouring oil into the engine motor car. Energy fuel concept.

How to Find Out What Engine Oil Your Car Takes

Recently bought a car and not sure which sort of engine oil it uses?

There are loads of different specs of engine oil represented by different letters – and this is often where buying engine oil can get confusing. Car manufacturers each have their own oil grade specification which they recommend you use in their cars, so make sure you use a product that lists your car’s manufacturer spec.

There are several ways to find out what engine oil you need for your car, including:

  • Redex Oil Checker – find recommended engine oils by entering your reg number or vehicle make and model in to our handy car oil finder.
  • Vehicle handbook – always check your car’s handbook for recommended oil types. Don’t have the original manual? It may be available online.
  • Local garage – your local mechanic should be able to tell you the type of oil your car needs.
  • Owners’ sites and forums – if you want recommendations about the best engine oil to use in your car, owners’ forums can be a valuable source of help and advice.
  • Select motoring retailers – several online motoring stores let you search for engine oil based on your reg number. In-store experts should also be able to advise on compatible oils for your car.

male customer buying engine lubricating oil in the car supermarket. Difficult decision which motor oil to buy

What Do the Letters and Numbers on Engine Oil Mean?

All engine oils are given a grade based on their viscosity level and winter temperature protection. This is represented by the letters and numbers assigned to each type of oil, e.g., ‘5W30’ or ‘10W20’.

Most modern engine oils are what we call multi-grade oils. They’re designed to offer optimal engine protection in both summer and winter driving conditions, so drivers don’t have to change engine oil at different times of year.

Taking 5W-30 as an example, let’s have a quick look at what this grade of oil offers in terms of engine protection.

Firstly, the ‘5W’ means it has a cold temperature rating of -25°C, meaning it’s more than capable of protecting car engines in the typical UK or European winter. Next, the ‘30’ indicates a thicker viscosity, which counteracts the high winter temperature rating to ensure that the engine is adequately protected during warmer-climate driving.

As a driver, understanding engine oil grades can help you choose the right oil for your climate, environment, and typical driving conditions.

The lower the number, the greater the winter temperature protection, as highlighted in the following table:

‘W’ Oil Viscosity Winter Temperature Protection
20W -10°C
15W -15°C
10W -20°C
5W -25°C
0W -30°C

What’s the Difference Between Fully Synthetic, Part-Synthetic and Non-Synthetic Oil?

Ever wondered why there’s such a difference in price between different brands of engine oil?

The main difference is that synthetic engine oil has been chemically synthesised in a laboratory to maximise performance, lubrication, and protection. Non-synthetic oil, on the other hand, is a type of refined crude oil that isn’t purified for use in car engines.

Here’s a brief look at the pros and cons of both synthetic and non-synthetic oil:

The Pros and Cons of Fully Synthetic Engine Oil

Fully synthetic oil is considered the best engine oil you can use in your car. That’s because it provides maximum lubrication and temperature protection, while also being more environmentally friendly than other types of oil.

At Redex, we only manufacture fully synthetic motor oil because we believe it provides the best protection for your engine. Find out more about the pros and cons of fully synthetic oil below.


  • Lasts longer between oil changes – you don’t have to change it as often, which is convenient, better for the environment as there’s less waste and can help offset the cost of spending more on the oil.
  • Improved fuel efficiency – synthetic oil flows better, allowing engine parts to turn more quickly for better efficiency and lower emissions.
  • Offers better protection – it withstands extreme temperatures better, in both hot and cold conditions. If you do a lot of long distance driving or have a high performance car the engine is likely to get to higher temperatures, so a synthetic or part-synthetic oil is recommended.


  • The most expensive type of engine oil

Mechanic reading instructions manual and replacing broken part

The Pros and Cons of Part-Synthetic Engine Oil

Part-Synthetic oil is exactly as it sounds – a mixture of synthetic and traditional oil. It’s a step above non-synthetic oil and doesn’t cost as much as premium engine oils, but can’t deliver the same performance as fully-synthetic variants.


  • Cheaper than fully synthetic oil
  • Offer better protection and improved efficiency compared to traditional oil, but not to the standard of fully synthetic options.


  • Doesn’t provide the same protection as fully synthetic oils
  • It requires changing more often than premium synthetic engine oil

The Pros and Cons of Non-Synthetic Engine Oil

Non-synthetic oil is the traditional engine oil, and is less “clean” than synthetic versions which have been engineered to have fewer impurities, however it is not “bad” for your car.


  • Cheaper than synthetic engine oil
  • A good budget option


  • Needs changing more frequently than synthetic oil
  • Isn’t as clean or environmentally friendly, since impurities aren’t removed before use
  • Doesn’t offer the same level of protection against friction and extreme temperatures as synthetic oil, so can contribute to premature engine wear

As well as fully synthetic and non-synthetic engine oil, it’s also possible to buy part-synthetic varieties. These are essentially a blend of distilled and crude oils, and offer a budget-friendly way to strike the right balance between protection, performance, durability, and affordability.

We hope this guide helps when choosing oil for your car. Remember, the Redex Oil Finder makes it quick and easy to find the right engine oil based on your reg number. For more information and to view our full range of premium engine oils, click here

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