Choosing the right oil for your car is crucial for maintaining its performance and longevity. With so many options available, finding the perfect match can be overwhelming. In Savvy’s comprehensive guide, we help demystify the process of selecting the right oil for your car. From understanding viscosity to considering the manufacturer's recommendations, we'll cover everything you need to know to ensure your car's engine runs smoothly and efficiently.

How do I work out what oil my car takes?

Check the owner's manual

The first and most important step in determining the right oil for your car is to check the owner's manual. The manufacturer provides specific recommendations for the type and grade of oil suitable for your vehicle, as well as capacity for how much oil your car can take. Look for the section on “Engine Oil” or “Fluid Specifications”, where you'll find valuable information about viscosity, API (American Petroleum Institute) ratings and other essential details.

In addition to the owner's manual, you can also find specific oil recommendations on the manufacturer's website or official sources. Sticking to the manufacturer's recommendations ensures that you use oil that meets the required standards and maintains your car's warranty.

Understand viscosity

Viscosity is a critical factor when choosing engine oil. It refers to the oil's thickness or flow rate at different temperatures. In Australia, you'll often encounter two numbers in the oil specification, such as 5W-30 or 10W-40. The first number, followed by a “W” (winter), represents the oil's viscosity in cold temperatures, while the second number indicates its viscosity at operating temperatures.

For most Australian climates, multi-grade oils, such as 5W-30 or 10W-40, are suitable as they offer good performance in both cold and hot conditions. However, because our winters aren’t as cold as those in Europe or parts of America, it isn’t necessarily as vital to aim for a high-winter-performance oil.

Consider the oil rating

The API rating is another essential aspect of engine oil. It reflects the oil's quality and its ability to protect your car's engine. An API rating is usually structured in an “API SN” format, where the first letter is either S (petrol engine oil) or C (diesel engine oil) and the second is a rating from A-Z, which progresses in quality as the alphabet goes on. Ratings such as API SN or API SM are generally suitable for most modern cars, but always check before you use it.

There are other classifications in use in Australia, however, with some European and Japanese cars instead coming with ACEA (Association des Constructeurs Europeens d’Automobiles), ILSAC (International Lubricant Standardization and Approval Committee) and JASO (Japanese Automotive Standards Organisation) ratings.

Choose between conventional, synthetic or semi-synthetic

You'll find three main types of engine oil in Australia: mineral, synthetic and semi-synthetic.

• Mineral oil is the most affordable option and is suitable for older or vintage vehicles with lower performance requirements.
• Synthetic oil is more refined to offer superior performance, especially in extreme temperatures, and is typically more suitable for modern vehicles.
• Semi-synthetic oil combines the benefits of both conventional and synthetic oils, providing better protection than conventional oil at a more affordable price than full synthetic. This type of oil is sometimes used in high-performance and turbo-diesel cars.

Consider the driving conditions

Your driving habits and the environment in which you operate your car can impact your choice of engine oil. If you frequently drive in severe conditions, such as extreme temperatures, heavy traffic, or towing heavy loads, you may wish to use a higher-quality synthetic oil which provides better protection under challenging circumstances.

Pay attention to oil change intervals

Oil change intervals vary based on the type of oil you use and your driving conditions. Follow the recommended oil change schedule in your owner's manual to keep your engine running smoothly and to avoid potential damage caused by old or degraded oil. While some people change the oil themselves, it's generally recommended to consult a mechanic, especially for your first few oil changes. They'll ensure the correct oil is used, dispose of the used oil properly and replace the oil filter.

What happens if I use the wrong oil in my car?

If you accidentally have the wrong oil put in your car’s engine, either by you or your car service provider, it can potentially cause damage. However, this will depend on the nature of the incorrect oil. For instance, if it’s a similar viscosity oil to what you usually have and is semi-synthetic instead of mineral, the issue may not be as great as if the oil viscosities were vastly different. This may also be the case if mineral is used instead of synthetic.

If the oil is sufficiently different from the recommended type, many experts recommend draining the oil and replacing it. This is because using oil with the wrong viscosity can lead to insufficient lubrication, causing increased friction and wear on engine components. This can result in reduced performance and premature engine failure, with repairs often being costly if you have a particularly valuable or heavy-duty vehicle.

Similarly, putting too much oil in your car can be harmful. Excess oil creates pressure and can damage engine components like gaskets and seals. It can also a seep into the spark plugs, causing ignition problems. If you suspect you've overfilled your car's oil, it's crucial to get it professionally addressed to avoid further damage.

Why is my car leaking oil?

Oil leaks in cars can stem from several potential sources. Common culprits include:

• Worn-out gaskets or seals, which can degrade over time due to exposure to heat, pressure and engine fluids. When they fail, oil can leak out.
• Loose or improperly installed oil drain plugs, which can cause oil to seep out from the oil pan. This can happen during an oil change if the plug isn't tightened sufficiently or if the threads are damaged.
• Cracked or damaged oil pans, which can occur due to road debris or impacts from objects on the road, leading to a rupture in the pan and subsequent oil leakage.
• Cracked engine blocks or damaged cylinder heads. These problems typically require professional attention and may necessitate extensive repairs.

Regardless of the cause, it's important to address oil leaks promptly to prevent further damage to the engine and to avoid potential safety hazards. If you notice oil spots under your car or detect a burning oil smell, it's advisable to have your vehicle inspected by a qualified mechanic to determine the source of the leak and take appropriate corrective action.

How do I check the oil in my car?

Checking your car's oil level is a simple yet important routine that should be performed on a regular basis as well as before long journeys. Here's what to do:

1. Park on level ground and turn off the engine. Wait for a few minutes to let the oil settle back into the crankcase.
2. Open the bonnet.
3. Identify the oil dipstick. This is a looped or ringed pull-out tab with an oil gauge on the end.
4. Pull out the dipstick, wipe it clean with a lint-free cloth and reinsert it fully.
5. Pull out the dipstick again and check the oil level. There will be markings on the dipstick indicating the recommended minimum and maximum oil levels. The oil should be between these markings.
6. Inspect the oil colour and consistency. While you have the dipstick out, you can also check the oil's colour and consistency. Fresh oil is usually amber or light brown and somewhat translucent. If the oil appears dark, gritty, or has a burnt smell, it may be time for an oil change.

How do I dispose of car oil?

You must never pour motor oil down drains, onto the ground or into bins, as this can lead to environmental contamination. To dispose of car oil responsibly, begin by draining the used oil from your vehicle's engine into a secure, leak-proof container designed for storing motor oil. Once collected, ensure the container is tightly sealed to prevent leaks during transportation. Locate a nearby recycling centre, auto parts store or service station that accepts used motor oil for recycling. Transport the sealed container to the designated drop-off location, following any specific guidelines provided by the facility. You may also be able to recycle used oil filters and rags.