Engine Oil

Whether it's a high performance sportscar, family people mover, rugged 4WD or just an old clunker we have the right engine oil to suit. Stocking an extensive array of brands and viscosities means whether it's a 10w30 semi synthetic engine oil, a 5w30 full synthetic engine oil or a basic mineral oil, we cater for your vehicle and driving style. Our partnerships with companies such as Penrite, Castrol, Nulon, and other leading brands ensure you have the cutting edge technology and highest grade formulations when it comes to the right engine oil for vehicle.

Choosing the Right Engine Oil

When choosing a motor oil for your car, the most important thing is the viscosity and the easiest way to pick the best engine oils for your car is to consult the owner's manual. Different engines require different viscosity engine oil to protect and operate correctly, depending on the manufacturer specifications. In simple terms, viscosity just means thickness. A low viscosity or light weight engine oil will appear smooth and flowing like water, however a higher viscosity or heavier oil will appear thicker, similar to honey or maple syrup.

What Is the Difference Between a Mineral Engine Oil and Synthetic Engine Oil?

Designed to suit a range of engine types, applications, driving styles and budgets, one of the main variations between oils are whether they are a fully synthetic, semi-synthetic, or mineral based engine oil.

• Mineral oils use more base oils and suit every-day use and are usually the right oil for older vehicles. However, for higher levels of protection and cleaning under intense driving conditions, semi-synthetic and full synthetic engine oils can be a better option.
• Semi-synthetic engine oils are a great middle ground, featuring some of the best bits of the full synthetic option whilst offering a well-performing lubrication solution that is friendly to your wallet. These engine oils work by offering better resistance to friction on metal surfaces in both low and high operating temperatures when compared to a mineral engine oil.
• Full synthetic engine oil will undergo an extensive lab treatment to provide a mixture of chemical additives and oil that make them perform significantly better than their mineral base oil counterparts. Apart from better extreme temperature performance, synthetic engine oils are formulated to provide low sludge and less corrosion formation as well as containing better detergents when you compare with mineral and synthetic oils. They also provide greater fuel economy based on their low viscosity. Keep in mind that the refining process is expensive and lengthy typically making synthetic engine oils the most expensive on the market.

FAQs for Engine Oil

What Oil Does My Car Take?

There are several ways to determine what oil your car needs. Your owner’s manual will list the recommended viscosity grade and specification for your engine. You can also use a registration lookup tool such as Repco’s Rego Search function to identify the correct oil based on your vehicle’s make and model.

If you have a spare top-up bottle from a recent service, the label will confirm the oil grade previously used. The most important factor is ensuring the oil meets the manufacturer’s required viscosity and performance standards to maintain proper lubrication, fuel efficiency, and long-term engine protection.

How To Check Your Engine Oil

1. Park your vehicle on level ground, engage the parking brake, and switch off the engine. Allow a few minutes for the oil to settle.
2. Open the bonnet and locate the dipstick, usually identified by a bright handle positioned near the oil filler cap, often marked with an oil can symbol.
3. Remove the dipstick and wipe it clean with a cloth, then fully reinsert it before pulling it out again to read the level.
4. The oil should sit between the minimum and maximum marks. If it is below the minimum mark, top up using the recommended oil grade.

How To Dispose of Motor Oil

Never dispose of used oil down household drains, into garden soil, or in general waste bins. Engine oil is harmful to the environment and must be handled responsibly.

Instead, take used oil to a local recycling facility such as a council landfill site, transfer station, or waste management centre. Many councils operate household chemical disposal programs that accept engine oil, oil filters, and contaminated containers. Some service stations may also accept used oil for recycling.

What Does 5W30 Oil Mean?

The number on your engine oil container refers to its viscosity rating. Viscosity describes how thick or thin the oil is at certain temperatures. The number followed by “W” indicates cold temperature performance, while the second number represents viscosity at normal engine operating temperature.

A lower first number means the oil flows more easily during cold starts, helping protect engine components sooner. The second number ensures the oil maintains adequate thickness once the engine reaches operating temperature.

Can I Use 10W30 Oil Instead of 5W30?

Both 10W30 and 5W30 oils share the same viscosity rating at operating temperature, meaning they perform similarly once the engine is warm. However, 5W30 flows more easily in cold conditions, which can improve lubrication during start-up.

While substitution may be acceptable in some situations, it is always best to follow your owner’s manual recommendations to ensure optimal engine performance and long-term reliability.

How Often Do You Need To Change Your Oil?

Oil changes should be carried out according to the servicing schedule specified by your vehicle’s manufacturer. This may be every 3–6 months or after a set kilometre interval. You may need to change your oil more often if you regularly tow heavy loads, drive in dusty environments, or operate in stop-start traffic.

Short trips and infrequent driving can also accelerate oil breakdown due to moisture build-up inside the engine. Regular oil changes help remove contaminants and maintain consistent engine protection.

Can I Mix Different Types of Engine Oil?

It is not generally recommended to mix different oil types, such as synthetic and conventional oils, as this can alter additive performance and viscosity characteristics.

To maintain consistent lubrication and protection, always use the oil grade and specification listed in your owner’s manual. If unsure, confirm compatibility before topping up or performing an oil change.

Trust Repco for All Your Automotive Oil and Fluid Needs

Providing not just quality lubricating engine oils for cars and trucks, we also stock a vast category of specialty oils such as motorcycle oils, small engine & garden equipment oils as well as all the fluid accessories and tools designed to drain and refill your engine.

With hundreds of stores nationwide, you'll be sure to have a store location near you. Use our Rego Search function and instantly have your shopping experience catered to your car's make and model. We provide a click and collect service from your nearest Repco store, or we can even provide delivery services to get it to you fast.