Engine oil buying guide | Finder

Engine Oil Finder

We’ll show you how to choose the best engine oil to keep your car running smoothly.

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Best Engine Oils

Best Rated Engine Oils Brand: Nulon

Top rated for oil quality, Nulon won the Finder Award for the best engine oil brand this year. It also rated well for peformance, packaging design and value for money.

Key facts about comparing engine oil

  • Engine oil is one of the most crucial but often overlooked products that help keep your car on the road.
  • Oil provides lubrication to reduce friction between the engine's moving parts, preventing wear and potentially serious damage.
  • The most important factors to consider when choosing engine oil are the type of oil recommended in your car’s owner’s manual, the viscosity of the oil and the type of car you drive.

What types are available?

Before we go any further, we should point out that the most important thing you can do when choosing engine oil is to check your car's owner manual. This will tell you which oil to use. This information can also sometimes be found on the oil reservoir cap on the engine. If you still can't find what you're looking for, the service department of your local dealership should be able to help.

There are a few different types of oil available:

  • Mineral oil. Also known as conventional oil, mineral oils are refined from crude oil. They're cheaper than synthetic oils and are generally better for older engines.
  • Synthetic oil. Synthetic oils are man-made products that have been refined and modified to make them more durable. They're more expensive than other options but will last longer, and they're suited to high-performance vehicles.
  • Semi-synthetic (or synthetic blend) oil. A combination of conventional and synthetic oils, semi-synthetic oils offer many of the same features as synthetic products but with a more affordable price tag.

The other main way to distinguish between oils is to check their viscosity. Viscosity refers to the oil's thickness, and you can see this listed on oil labels with classifications like "5W-30".

These number-and-letter formulas reflect an oil's Society of Automotive Engineers (SAE) rating – the higher the number, the thicker the oil. An oil that's low in viscosity will flow faster, particularly when you first start your engine, but high-viscosity oils cope better at high temperatures.

So if an oil has a 5W-30 rating, the 5W reflects how the oil will flow at cold temperatures – the W stands for winter – while the 30 refers to its viscosity at hot temperatures.

How to compare engine oils

There are several factors you should consider before choosing an engine oil. Take the following factors into account when comparing your options.

What your car needs

Check the original equipment manufacturer's (OEM) recommended engine oil. You may be able to find this in the car owner's manual, on the oil reservoir cap or through the service department of your local dealership.

Retailers also make it easy to find the right oil. Browse engine oil online with a major automotive store and you'll be able to filter your search to find oils suitable for your car's make, model and engine type.

Viscosity

An oil’s SAE viscosity rating is always prominently displayed on the label. Check this rating to make sure it fits the recommended oil viscosity for your engine.

Type of fuel

The oil you choose will vary depending on whether your car runs on petrol, diesel or LPG. Check the label to determine whether an oil is suitable for your fuel type.

API or ACEA classification

Check the label to see whether there's an API or ACEA classification standard listed. This rating allows you to determine whether the oil is suitable for use in your engine, and standards are regularly updated as technology improves. We'll explain these standards in more detail further down the page.

Brand

The safest option when buying engine oil is to choose a recognised brand. This will ensure that you buy a high-quality product to maintain your engine and improve performance. You'll typically need to spend a little extra to choose a quality brand, but that added cost is still a whole lot cheaper than replacing an entire engine.

Price

If you’re buying mineral oil, you can expect to pay approximately $25-$50 for 5L for most products. Semi-synthetic oils are generally in the $30-$60 range for 5L, while synthetic oils are the most expensive of the bunch and are usually priced between $40 and $90 per 5L.

API and ACEA oil standards

As if engine oil labels weren't already confusing enough, there are a couple of other acronyms to keep an eye out for on the bottle. These are API, which stands for the American Petroleum Institute, and ACEA (which is the European Automobile Manufacturers Association). For example, you might see the terms "API SN/CF" and "ACEA C3/B4" on a label.

These terms refer to oil classification standards determined by these two organisations. These standards set minimum oil performance requirements, and they're regularly updated as oil and engine technology improve.

Under the API standard, which is most commonly used in Australia, the letter "S" is used for petrol engine oils and "C" is used for diesel. For petrol engines, SP is the latest standard and was introduced in May 2020. SN oil is for 2020 and older automotive engines, SM is for 2010 and older automotive engines, and so on as you work through the alphabet in reverse order. You can check out the full classifications here.

ACEA uses a different rating system, so check the latest classification on the organisation's website.

Three things to consider

There are a few other important factors to consider when choosing and using engine oil:

  • The importance of regular oil changes. Oil works hard to protect your engine, and over time, it can wear down and collect contaminants. This reduces its ability to protect your engine, which is why you need to change your oil regularly. As for how often it needs changing, check the manufacturer's recommendation. Find out more about how to look after your car with our 31 car maintenance tips.
  • How you use your car. Different driving conditions (such as towing heavy loads or spending lots of time in stop-start traffic) can also affect oil change frequency. To check oil levels, you can pop the bonnet and pull out the dipstick, while some modern cars will automatically notify you when the oil level gets too low.
  • High-mileage oil. If your engine has more than 100,000km on the clock and is starting to show its age, you may need to consider switching to a high-mileage oil. These products contain additives designed to reduce oil leaks and extend the life of an engine.

Ready to start shopping? Check out our guide to the top sites to buy automotive accessories online.

Best rated engine oil brand award breakdown

Total Score Overall rating Value for Money Performance Packaging/Design Oil quality
Nulon 8.38 4.64 4.24 4.52 4.4 4.62
Penrite Oil 8.23 4.49 4.2 4.51 4.27 4.57
Other 8.2 4.56 3.88 4.56 3.96 4.64
Valvoline 8.17 4.43 4.12 4.59 4.41 4.61
AMSOIL 8 4.2 4.4 4.4 4.6 4.4
Castrol 7.93 4.31 4.08 4.37 4.12 4.35
Gulf Western 7.9 4.26 4.43 4.57 4.13 4.39
Shell 7.86 4.26 4.06 4.26 4.18 4.28
Mobil 7.79 4.29 4.08 4.27 4.06 4.18
Data: Finder Retail Brand Survey, 2020, Kantar. Metric out of 5 stars unless indicated. Methodology and more info. Kantar logo

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