How to Change the Oil in Your NB Miata: A Simple DIY Guide

Eiginber Belarmino
September 24, 2024

Changing the oil in your NB Miata is one of the easiest yet most impactful ways to keep your car running smoothly. Regular oil changes not only ensure peak performance but also protect your engine from wear and tear over time. The engine relies on clean oil to reduce friction between its moving parts, dissipate heat, and prevent the buildup of harmful sludge. By keeping your oil fresh, you’re prolonging the life of your Miata’s engine and avoiding expensive repairs. Whether you’re a seasoned car enthusiast or a first-time DIYer, this step-by-step guide will walk you through the entire oil change process. With the right tools and a bit of patience, you’ll have your Miata ready to hit the road in no time.

Tools and Materials

Before diving under the hood, it’s important to gather all the necessary tools and materials. Being prepared will save you time and prevent unnecessary trips to the store mid-job. For this oil change, you’ll need about 5 liters of 10W-40 synthetic oil—though the Miata typically only takes about 4.5 liters. Synthetic oil is highly recommended for better engine protection and longevity, especially if you drive in varying weather conditions. You’ll also need a new oil filter, which you can find at your local auto parts store or online. Be sure to check your manual for the correct part number.

To get the job done right, you’ll need a 19mm socket wrench for the oil drain plug and a 10mm socket wrench if you plan to remove the engine undertray (this is optional but can make the process smoother). An oil catch pan, funnel, jack, and jack stands are also essential. Safety gear is important too—wear gloves to protect your hands from hot oil and safety glasses in case of splashes. While not strictly necessary, tools like a magnetic tray for bolts and an oil filter wrench can make things easier, especially if this is your first time changing oil.

Step 1: Lifting the Car (Optional)

Depending on your Miata’s ride height, you might be able to reach the oil drain plug and filter without lifting the car. However, if your Miata has been lowered, or you just want more space to work, you’ll need to raise the car. Place a hydraulic jack under the designated jacking points (typically the reinforced sections of the frame), and lift the car just enough to access the undercarriage. Once raised, be sure to support the car with jack stands. Never work under a vehicle supported only by a jack, as this could lead to serious injury if the jack fails.

If you’re comfortable, jacking up just one side of the car—usually the driver’s side—might be enough for this job. The oil drain plug is slightly off-center on the passenger side, allowing for better oil flow.

Step 2: Locate and Loosen the Oil Drain Plug

With the car lifted (or not, depending on your preference), the next step is to locate the oil drain plug. On the NB Miata, the plug is positioned on the passenger side of the oil pan at the lowest point to ensure maximum drainage. Place your oil catch pan directly under the plug. Using a 19mm socket wrench, begin loosening the drain plug by turning it counterclockwise. Once it’s loose enough, you can finish unscrewing it by hand, but be prepared for the oil to start flowing quickly. It’s a good idea to keep pressure on the bolt until you’re ready to pull it free to avoid getting oil on your hands.

Let the oil drain fully. This process may take around 20 to 30 minutes, so be patient. If the oil stream starts to splatter, especially in windy conditions, you can use a piece of cardboard as a shield to keep things clean.

Step 3: Remove the Engine Undertray (Optional)

If your NB Miata is equipped with an undertray (sometimes called a splash guard), removing it can give you better access to the oil filter. This step is optional, but if you have trouble reaching the filter, it might be worth the extra effort. The undertray is secured by several 10mm bolts. Use your socket wrench to remove them, and place the bolts in a magnetic tray or another safe spot so you don’t lose them. Once the undertray is off, you’ll have a clearer view of the filter and more room to work.

Step 4: Remove the Old Oil Filter

Now, it’s time to remove the old oil filter. On the NB Miata, the oil filter is located on the right side of the engine under the intake manifold. It can be a little tricky to reach, which is why some Miata owners choose to remove the undertray first. Once you’ve located the filter, turn it counterclockwise by hand to unscrew it. If it’s stuck, an oil filter wrench can help you get the job done.

Be careful when removing the filter, as oil will likely spill out. To minimize the mess, try to position a rag or towel under the filter as you unscrew it. Once the filter is free, carefully set it aside. Don’t forget to clean the area where the filter was seated to remove any old oil or debris.

Step 5: Install the New Oil Filter

Before you install the new oil filter, take a moment to prepare it. Dip your finger into the fresh oil and apply a thin layer around the rubber O-ring of the new filter. This will ensure a proper seal and make it easier to remove during your next oil change.

To install the new filter, simply screw it on by hand, turning it clockwise until snug. Never use a wrench to tighten the oil filter—hand-tightening is sufficient and will prevent damage to the threads or the O-ring.

Step 6: Replace the Oil Drain Plug

By now, the old oil should have completely drained from the engine. Wipe down the area around the drain plug with a rag to ensure it’s clean before reattaching the plug. Hand-tighten the plug first, then use your 19mm socket wrench to finish the job. Be sure not to overtighten, as this could strip the threads or crack the oil pan. If you have a torque wrench, aim for a torque setting between 22 and 30 ft-lbs (29-41 N-m).

Step 7: Refill the Engine with Oil

With the old oil drained and the new filter in place, it’s time to add fresh oil. Remove the oil filler cap, which is usually marked with an oil can symbol, and insert a funnel into the opening. Slowly pour in approximately 4.5 liters of 10W-40 synthetic oil. Be sure to go slowly and check the oil level periodically using the dipstick to avoid overfilling.

Step 8: Check Oil Levels and Start the Engine

Once you’ve poured in the oil, check the level using the dipstick. Insert the dipstick fully, then remove it and look at the markings. You want the oil level to be at or just below the “F” (full) mark. If needed, add more oil in small amounts until the level is just right.

After you’ve confirmed the oil level, replace the oil filler cap and start the engine. Let it idle for a few minutes to circulate the new oil throughout the system. Keep an eye on the oil pressure gauge to ensure everything is running smoothly.

Step 9: Lower the Car and Final Check

Now that the oil change is almost complete, it’s time to lower the car and perform a final check. Lift the car slightly with the jack to remove the jack stands, then carefully lower it back to the ground. Once the car is securely on the ground, inspect the area around the oil drain plug and oil filter for any signs of leakage.

Step 10: Dispose of Used Oil Properly

The final step in your oil change process is to properly dispose of the used oil and old filter. Most auto parts stores and recycling centers accept used oil and filters for free. Pour the old oil into a sealed container and take it to a designated drop-off location. Never dispose of oil in the trash or down a drain, as it’s harmful to the environment.


When selecting oil, always check your Miata’s manual for the manufacturer’s recommended type. In warmer climates, 10W-40 offers better protection, but if you live in a colder region, 5W-30 might be more appropriate. Tighten the oil filter by hand only to avoid over-compression of the O-ring, which can cause leaks. Lastly, be cautious not to overfill the engine, as too much oil can lead to pressure issues and potential engine damage.

Regular oil changes are essential to keeping your NB Miata performing at its best. By following this step-by-step guide, you can take control of your car’s maintenance and save money in the process. Changing your own oil isn’t just cost-effective—it’s a rewarding DIY project that ensures your car is always road-ready. So grab your tools, take your time, and enjoy the satisfaction of completing this essential task on your own.

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