What kind of engine oil should I use?
The right oil is the one your vehicle’s manufacturer specifies in the owner's manual, typically a synthetic oil with a low-viscosity grade such as 0W-20 or 5W-30. Following the OEM recommendation and using an oil with current industry certifications is essential.
Beyond the manual, choosing engine oil depends on your engine design, climate, and how you drive. This article breaks down oil types, viscosity grades, the standards to look for on the label, and practical tips to select and maintain the right oil for your vehicle.
Oil types and when to use them
Knowing the main categories helps you pick the right product for your car and budget. The following overview covers common options and their typical use cases.
Common oil types
- Conventional (mineral) oil: Usually the least expensive option; suitable for older vehicles or where high-performance demands are not present.
- Synthetic blend: A mix of conventional and synthetic base oils; offers better protection and stability than conventional at a lower cost than full synthetic.
- Full synthetic oil: Provides the highest level of protection, oxidation resistance, and performance, especially in modern engines, turbocharged applications, extreme temperatures, and long-drain intervals.
- High-mileage oil: Formulated with seal conditioners and additives aimed at engines with high mileage (typically 75,000 miles or more) to help reduce leaks and reduce wear.
Choosing the right type depends on engine age, driving conditions, and manufacturer guidance. In most cases, modern engines benefit from synthetic or synthetic-blend oils, while older engines on a tight budget may be adequately served by conventional oil.
Viscosity and climate: choosing the right grade
Viscosity describes how thick the oil is, with the first number (before the W) indicating cold-start behavior and the second number indicating high-temperature protection. Use the grade recommended by your manual, but here is a practical snapshot of typical choices by climate and engine needs.
Typical viscosity grades
- 0W-20: Excellent for cold starts; common in newer engines designed for fuel efficiency.
- 5W-30: A widely used, versatile grade suitable for many climates and engines.
- 0W-40 / 5W-40: Higher-temperature protection and performance for turbocharged or high-load engines.
- 10W-30: A workable option in warmer climates or older engines that tolerate higher viscosity.
Using the wrong viscosity can affect lubrication, fuel economy, and engine wear. Always follow the official specification for your vehicle and consider climate and driving style when selecting a grade.
Standards and certifications to look for
Oil labels carry standards that ensure a minimum level of performance, protection, and compatibility with emissions systems. The right combination helps with reliability and warranty adherence.
Key standards and approvals
- API SP (and newer API service classifications as they are released)
- ILSAC GF-6 family (GF-6A, GF-6B) for gasoline engines; some regions may reference updated GF-6 specifications
- ACEA ratings for European vehicles (where required by the manufacturer)
- OEM approvals and numbers (examples include VW 502.00/505.00, BMW LL-01, MB 229.x, Toyota/ Lexus, Honda HTO-6, etc.)
- Diesel engine specs where applicable (e.g., CK-4 for certain diesel engines)
Oils carrying these certifications align with modern engine protections and can be important for warranty compliance and long-term durability.
Practical maintenance guidelines
Oil change intervals depend on oil type, vehicle design, and driving conditions. Modern cars with synthetic oils often enable longer drains, but always verify with the manual or dealer guidance. Here are general guidelines to consider.
- Follow the owner’s manual or the vehicle’s service indicator (oil life monitor) to determine when to change oil.
- Consider driving conditions: frequent short trips, towing, or extreme temperatures can shorten drain intervals.
- Use the recommended viscosity and oil type; if you must switch types, follow manufacturer directions and avoid mixing different base oils unnecessarily.
- Inspect oil level and condition regularly; dark oil can be normal, but burnt or gritty oil signals a problem requiring service.
Sticking to the recommended interval and using the right oil type helps protect the engine, maintain efficiency, and preserve warranty coverage where required.
How to read the oil label
Understanding the labeling helps you choose a product that matches your vehicle’s requirements and climate. The main elements to check are:
Key markings to look for on a bottle
- SAE viscosity grade (for example, 0W-20, 5W-30)
- API service rating (for example, SP or newer)
- ILSAC certification (GF-6 family and related approvals)
- OEM approvals or specifications (as required by your vehicle)
- Notes on synthetic vs conventional base and any notes about high-mileage formulations
Choosing oil with the correct certifications and viscosity supports engine protection and ensures compatibility with emissions systems and warranty terms.
Conclusion and quick takeaway
The best engine oil for your car is the one specified by the manufacturer, with the appropriate viscosity and current API/ILSAC standards and OEM approvals if your vehicle requires them. Climate, driving habits, and engine age influence the final choice and how often you should change the oil. Always start with the owner’s manual or consult a trusted mechanic for personalized guidance.
Summary: Always follow the manufacturer’s specification, choose the correct viscosity for your climate and engine design, select an oil with current certifications (such as API SP and ILSAC GF-6), and adhere to recommended change intervals. When in doubt, a dealership or qualified technician can confirm the best option for your vehicle.
What happens if I put 5W-30 instead of 5W-20?
Putting 5W-30 in an engine that calls for 5W-20 is generally not a major issue for short-term use, but it can lead to slightly reduced fuel efficiency and may affect variable valve timing systems. Over time, the thicker oil may cause slightly more wear, so it's best to switch back to the recommended 5W-20 at your next oil change.
Effects of using 5W-30 instead of 5W-20
- Slightly lower fuel economy: 5W-30 is thicker at operating temperature, so the engine has to work slightly harder to pump it, which can lead to a small reduction in gas mileage.
- Impact on variable systems: Modern engines with variable valve timing (VVT) or similar systems rely on specific oil viscosity for proper function. A thicker oil can alter the system's pressure and performance, though this is often a minor effect.
- Increased engine pressure: The increased thickness can lead to a slightly higher pressure inside the engine.
- Potential for minor wear: While the extra wear is very slight and unlikely to cause immediate damage, it's a consideration for long-term use, as the engine was designed for the thinner 5W-20 oil.
What to do
- Don't panic: Driving with 5W-30 for a short period will not cause immediate, significant damage to most engines.
- Change to the correct oil: At your next opportunity, get an oil change and replace the 5W-30 with the manufacturer's recommended 5W-20 oil.
- Monitor your engine: Listen for any unusual noises and check for any changes in performance as you continue to drive.
- Check the owner's manual: Always refer to your vehicle's owner's manual for the specific oil viscosity recommended for your engine, as it's the most reliable source of information.
How do you determine what engine oil to use?
To check your engine oil type, consult your car's owner's manual, look for the required oil specification on the oil filler cap or dipstick, or use an online oil finder tool. The correct oil is specified by its viscosity grade (e.g., 5W-30) and any other manufacturer specifications listed in your manual.
Methods to check engine oil type
- Consult the owner's manual: This is the most reliable source for the exact oil viscosity and specifications your car requires, including whether it needs conventional, synthetic, or a blend.
- Check the oil filler cap or dipstick: The correct viscosity grade is often printed directly on the oil filler cap or sometimes on the dipstick itself.
- Use an online oil finder tool: Many oil manufacturers and auto parts retailers have online tools where you can enter your vehicle's make, model, and year to find the recommended oil type.
- Examine the current oil bottle: If you have the old oil bottle, the product name, viscosity, and specifications will be on the back, as noted by this YouTube video.
What the numbers mean (e.g., 5W-30)
- The first number and 'W' (e.g., 5W): This indicates the oil's viscosity at cold temperatures. A lower number means the oil flows better in cold weather, which is important for starting the engine on cold days.
- The second number (e.g., 30): This indicates the oil's viscosity at normal operating temperature.
- High-mileage engines: If your car has over 75,000 miles, a high-mileage oil might be a good option, as it is formulated to help with wear and tear.
How do I know if my car needs synthetic or conventional oil?
Check your owner's manual to determine if your car requires synthetic or conventional oil; the manual will specify the correct type and viscosity. Modern vehicles, especially those with high-performance, turbocharged, or GDI engines, often require synthetic oil due to tighter tolerances and higher operating stresses.
How to find the right oil
- Owner's manual: This is the most reliable source, as it will state the specific viscosity grade (e.g., 5W-30) and performance specifications recommended by the manufacturer.
- Online lookup tools: Many oil manufacturers and auto parts stores have online tools where you can enter your car's year, make, and model to find the recommended oil type.
- Oil cap: The correct oil type and viscosity grade may also be stamped on the engine's oil filler cap.
When to consider synthetic oil
- Newer or high-performance vehicles: Many newer cars require synthetic oil for optimal performance and protection.
- Harsh driving conditions: If you frequently drive in extreme temperatures, tow heavy loads, or drive in dusty or stop-and-go traffic, synthetic oil's superior resistance to breakdown can be beneficial.
- Longer change intervals: Synthetic oil can often last longer than conventional oil, meaning fewer oil changes are needed.
When to consider conventional or high-mileage oil
- Older vehicles: If your vehicle has high mileage and an older, simpler engine design, conventional or high-mileage oil may be appropriate. High-mileage formulas contain additives to condition seals and reduce oil consumption in older engines.
Does it matter what engine oil I use?
Yes, it matters what oil you put in your car; using the wrong type can lead to engine damage, reduced performance, and a shortened lifespan. Always use the oil viscosity and type (conventional, synthetic, or blend) recommended in your car's owner's manual, as different engines require specific lubrication properties.
Why the correct oil is important
- Lubrication: The right oil lubricates moving engine parts to minimize friction, which is essential for preventing wear and tear.
- Protection: It protects against excessive heat and sludge buildup, which can impair engine function over time.
- Performance: Using the correct oil maintains engine performance and can even improve fuel efficiency.
- Warranty: Using the wrong oil may void your vehicle's warranty, especially with many newer vehicles that require full synthetic oil.
How to choose the right oil
- Check your owner's manual: This is the most reliable source for the specific oil viscosity grade (e.g., 5W-30, 10W-30) and type (conventional, synthetic, blend) your engine requires.
- Consider the viscosity numbers: The numbers on the oil container indicate its viscosity. The first number (e.g., the "5" in 5W-30) refers to how the oil flows in cold temperatures (W = Winter), and the second number (e.g., the "30") refers to how it flows when the engine is hot.
- Look for specific certifications: Your manual might also list specific certifications or specifications your oil needs to meet. Look for these on the bottle.
- Don't mix: While occasionally mixing oil types won't cause immediate damage, it's best to stick to one type. If you need to top off, only do so with the exact type specified in your manual.
- When in doubt, ask: If you're unsure, ask a dealership or mechanic what oil your car needs.
