The Ultimate Guide to Choosing the Right Engine Oil for Your Car

Every day we see many customers unsure about which engine oil is best for their car. With so many options—different types, viscosities, and brands—it can get confusing. But choosing the right oil is crucial for your engine’s health, performance, and longevity.

At JR Auto Service Gold Coast, we only use high-quality oils  that meet your vehicle’s specific needs. Ensuring your car runs smoothly and efficiently is our top priority.

In this guide, I’ll break down the most common questions about engine oil so you can make the best decision for your vehicle.

 

Does It Matter Which Oil I Put in My Car?

Yes, absolutely! Using the correct engine oil ensures:

✔ Proper lubrication to reduce friction and wear
✔ Improved fuel efficiency
✔ Protection against sludge and deposits
✔ A longer lifespan for your engine

Your car’s manufacturer specifies the recommended oil grade and type, and using the wrong one can affect performance, fuel economy, and even lead to costly engine damage.

 

What Happens If You Put the Wrong Oil in Your Car?

Using the wrong oil can cause:

• Increased engine wear – If the oil is too thin or thick, it won’t lubricate the engine properly.
• Reduced fuel efficiency – Incorrect viscosity can cause the engine to work harder, consuming more fuel.
• Difficulty starting in extreme temperatures – The wrong oil may not flow well in cold weather or protect effectively in hot conditions.
• Sludge buildup – Poor-quality or incorrect oil can lead to deposits that block engine passages.

If you’ve accidentally used the wrong oil, it’s best to drain and replace it with the correct type as soon as possible.

Should I Use 5W30 or 5W40 for My Car?

Both 5W30 and 5W40 are common multigrade oils, but their difference lies in viscosity:

• 5W30 – Thinner at high temperatures, making it ideal for colder climates and ensuring smooth oil flow.
• 5W40 – Slightly thicker when hot, offering better protection in warmer climates or for high-performance engines.

Always check your vehicle’s manual to see which viscosity grade is recommended for your engine.

 

Can I Put 10W40 Instead of 5W30?

While 10W40 is thicker at high temperatures than 5W30, using it in an engine designed for 5W30 may cause problems, including:

• Poor oil circulation – Especially in cold starts, leading to increased engine wear.
• Reduced fuel efficiency – Thicker oil can create more resistance, making your engine work harder.
• Potential damage – If the manufacturer recommends 5W30, it’s best to stick with it.

If you’re unsure, check your owner’s manual or speak with a professional.

 

How Often Should Engine Oil Be Changed?

The frequency of oil changes depends on your vehicle type, driving conditions, and oil quality. At JR Auto Service we recommend replacing in you oil  General guidelines:

• Every 7,000 km or 6 months (whichever comes first) for semi-synthetic oils.
• Every 10,000 km (whichever comes first) for full-synthetic oil.

Modern vehicles using high-quality synthetic oil may go longer between changes, but always refer to your service manual for specific recommendations.

 

How to Choose the Right Engine Oil for Your Car?

Consider these factors when selecting engine oil:

• Viscosity Grade – Follow the manufacturer’s recommendation (e.g., 5W30, 10W40).
• Oil Type – Full synthetic,semi-synthetic or mineral.
• Driving Conditions – Extreme temperatures, stop-and-go traffic, or high mileage may require special formulations.

If you’re still unsure, feel free to ask us at JR Auto Service Gold Coast—we’re happy to help!

 

Can I Use Any 5W30 Oil in My Car?

Not all 5W30 oils are the same. Look for manufacturer approvals and industry certifications, such as:

• API SN, SP – American Petroleum Institute standards for modern engines.
• ACEA C3, A5/B5 – European certifications for high-performance and fuel-efficient oils.
• Manufacturer-Specific Standards – Some brands, like VW 504 00 or Ford WSS-M2C913-C, have their own oil requirements.

Using a high-quality, approved oil ensures optimal performance and protection for your engine.

 

Does My Car Need Regular or Synthetic Oil?

Synthetic oil is generally recommended for modern engines because it offers:

✔ Better protection at extreme temperatures
✔ Reduced sludge and deposits
✔ Longer oil change intervals

However, some older cars may still run efficiently on conventional oil. Again, check your car’s manual to determine the best option.

At JR Auto Service Gold Coast, we only use high-quality synthetic and conventional oils based on your car’s needs to ensure maximum efficiency and protection.

 

What Cars Use 10W40 Oil?

10W40 oil is typically used for:

• High-mileage vehicles that need extra engine protection.
• Older engines prone to wear and oil leaks.
• Warmer climates, where thicker oil can provide better protection.

If your manual recommends 10W40, it’s best to stick with it for proper lubrication and performance.

 

Can You Mix Synthetic Oil with Regular Oil?

While mixing synthetic and conventional oil is technically possible, it’s not recommended. Doing so can:

• Reduce the performance benefits of synthetic oil.
• Lead to inconsistent lubrication and potential engine deposits.
• Shorten oil change intervals.

If switching from conventional to synthetic oil, a full oil change is best rather than mixing the two.

 

Choosing the right engine oil is essential for maintaining performance, efficiency, and engine longevity. The best way to ensure you’re using the correct oil is to refer to your car’s manual and follow the manufacturer’s recommendations.

At JR Auto Service Gold Coast, we take engine health seriously, which is why we only use high-quality oils suited to your car’s specific needs. Whether you need an oil change, expert advice, or a full service, our team is here to help.

📍 Need an oil change or expert advice? Visit JR Auto Service Gold Coast today!

Got questions? Give us a call or drop by—we’re always happy to assist!

– Mari @ JR Auto Service Gold Coast