Is it okay to put a different type of oil in your car?

The short answer is generally no—stick to the oil type and viscosity your manufacturer specifies. Using an oil that doesn’t meet the engine’s requirements can reduce protection, hurt performance, and may affect warranties. In a pinch, you can top up with a closely matching grade, but you should switch back to the correct oil at the next service.

Understanding when and why this matters helps car owners avoid costly engine damage. This article explains what counts as a "different" oil, how to check compatibility, and best practices for topping up or changing oil so you keep your engine healthy and compliant with warranty terms. It covers conventional, synthetic, and blend options, common viscosity grades (like 0W-20 and 5W-30), and the importance of meeting API/ILSAC specifications.

What counts as a different type of oil?

There are several forms of motor oil, and they differ in base composition, additives, and viscosity. Here are the main categories and how they usually relate to a vehicle’s requirements.

• Conventional mineral oil: The traditional, least expensive option. Sufficient for many older engines or normal driving, but it can break down faster under high stress or extreme temperatures.


• Synthetic motor oil: Offers superior high-temperature stability, better wear protection, and longer change intervals. Many newer vehicles require or recommend synthetic oil.


• Synthetic blend: A middle ground between conventional and full synthetic—improved protection and stability without the full synthetic price tag.


• High-mileage and specialty formulas: Formulated with additives to condition seals and reduce oil consumption for engines with higher mileage or particular needs. These are not universally required and depend on vehicle design and wear.

The key takeaway from this list is that the right oil isn’t just about the base oil type; it must meet the vehicle’s required viscosity and performance specifications. Using an oil that doesn’t meet those specs can compromise lubrication and warranty coverage.

How to decide if you can switch oil types in practice

To determine whether you can use a different oil than the one originally specified, follow these guidelines.

1. Check your owner’s manual or the oil specification sticker under the hood for the exact viscosity (for example, 0W-20 or 5W-30) and the required specification (such as API SP and ILSAC GF-6).


2. Compare the current oil’s grade and specification to the manual’s requirements. If they match, topping up or replacing with the same grade is generally acceptable.


3. If you’re considering a different viscosity or a different type (e.g., conventional vs synthetic) in an emergency, ensure the alternative meets the same spec and is within a safe viscosity range for your climate and driving conditions.


4. Plan to revert to the exact recommended oil at the next oil change, and consult a dealer or mechanic if you’re unsure about compatibility or warranty implications.

Bottom line: The closer the substitute stays to the manufacturer’s specified oil, the better for your engine’s protection and warranty. When in doubt, seek professional guidance.

Mixing oils: good, bad, or indifferent?

Mixing different oil types or viscosities is generally not recommended, but may be acceptable in an emergency if the mixed oils both meet the vehicle’s spec. Mixing can alter the additive package and may not provide ideal protection. If you must mix, choose oils that share the same specification and as similar a viscosity as possible, and plan to drain and replace with the correct oil at the next opportunity.

Best practices for topping up and oil changes

To minimize risk and protect engine longevity, follow these practical guidelines when topping up or performing an oil change.

• Always use the exact viscosity and specification recommended by the manufacturer (e.g., 0W-20 API SP, GF-6, etc.).


• Top up with oil that matches the required spec; if that exact oil isn’t available, use the closest matching viscosity that still meets the spec.


• Avoid large differences in viscosity or switching between conventional and synthetic outside of what the manual allows; mixing is best avoided unless necessary in an emergency.


• When possible, perform oil changes with the exact oil type and grade specified, and schedule regular changes to maintain engine protection and warranty compliance.

Conclusion: Adhering to the manufacturer’s oil specifications is the most reliable way to protect engine life and keep warranties intact, while occasional emergencies can be managed with careful, spec-compliant substitutions.

Summary

Putting a different type of oil in your car isn’t a decision to take lightly. The safest approach is to use the oil type and viscosity your manufacturer specifies and to avoid mixing oils that don’t meet those specs. Synthetic oils, blends, or high-mileage formulas can offer advantages, but they must align with the engine’s design and warranty requirements. In emergencies, you can top up with a close substitute that meets the same specification, but plan a return to the correct oil at the next service to maintain optimal protection and performance.

What happens if you put a different type of oil in your car?

Putting the wrong type of oil in your car can lead to reduced engine performance, overheating, and accelerated wear, as it may not provide the proper lubrication and protection for your engine's components. The extent of the damage depends on the type of oil used, but consequences can range from minor issues like reduced fuel efficiency to severe engine damage over time, which could even lead to a complete engine failure and void your warranty. It's essential to consult your owner's manual to use the oil type and viscosity grade specified by the manufacturer. 
Potential consequences of using the wrong oil

• Inadequate lubrication: The wrong oil may not create a sufficient protective film between metal parts, leading to increased friction, wear, and potential damage to components like bearings and pistons. 
• Engine overheating: Oil helps dissipate heat. An oil that is too thick may not circulate properly to cool the engine, while an oil that is too thin can break down under high temperatures and lose its heat-managing properties, both leading to overheating. 
• Poor performance: You may experience reduced fuel economy as thicker oil creates more internal resistance, and other performance issues like a burning smell, engine noise, or smoke from the exhaust. 
• Seal damage and leaks: Thin oil can seep past seals and gaskets that were designed for a thicker oil, leading to leaks and lower oil levels. 
• Difficulty starting: Thicker oils become more viscous in cold weather, which can strain the battery and starter motor, making the engine harder to start. 

What to do if you used the wrong oil

• If you realize your mistake immediately after an oil change, drain the wrong oil and replace it with the correct one as soon as possible.
• The longer the wrong oil is left in the engine, the higher the risk of damage to sensitive components. 

What happens if I mix oil types in my car?

Putting the wrong oil in your car can lead to engine damage, reduced efficiency, and premature wear and tear because it won't provide adequate lubrication or cooling. This can manifest as overheating, poor performance, unusual noises, oil leaks, or even catastrophic engine failure over time. The severity of the damage depends on how different the wrong oil is from the manufacturer's recommendation, and in some cases, it could void your car's warranty. 
Potential consequences of using the wrong oil

• Inadequate lubrication: The wrong oil may be too thick or too thin, failing to create a proper protective film between moving parts. This leads to increased metal-on-metal friction, which can damage bearings, pistons, and the crankshaft. 
• Engine overheating: Oil helps dissipate engine heat. If the oil is too thick, it may not circulate efficiently, leading to overheating. If the oil is too thin, it can break down at high temperatures and lose its ability to manage heat. 
• Reduced fuel economy: Thicker oils can increase the engine's internal resistance, forcing it to work harder and consume more fuel. 
• Oil leaks: Thin oil may seep past seals and gaskets that were designed for a thicker viscosity, causing leaks. 
• Difficulty starting: Thicker oils become more viscous in cold weather, straining the battery and starter motor. 
• Engine damage: Over time, the increased friction and poor lubrication can cause significant damage to various engine components, potentially leading to a complete engine failure. 
• Voided warranty: Using the incorrect oil can be a reason for a manufacturer to deny a warranty claim if engine damage occurs. 

What to do if you used the wrong oil

• Get an oil change: If you notice any issues or remember putting in the wrong oil, get an oil change as soon as possible. It's best to correct the problem before damage occurs. 
• Check your owner's manual: Always refer to your owner's manual for the correct viscosity and specifications recommended by the manufacturer. 
• When mixing oils: If you absolutely have to mix oils because you are low and the correct brand is unavailable, ensure they have the same viscosity and grade and consider changing the oil sooner than scheduled, notes The Shop Manual. 

What happens if I put 5W-20 instead of 5w30?

Putting 5W-20 instead of 5W-30 oil means you are using a slightly thinner oil when the engine is hot. This can lead to slightly less engine protection, especially in hot weather or during heavy use, and a minor reduction in fuel economy. However, for most modern cars, the difference is minimal and there is no need for immediate concern unless your vehicle is a high-performance model, in which case you should consult your owner's manual and consider changing to the correct oil as soon as possible. 
Potential effects of using 5W-20 instead of 5W-30

• Reduced protection: 5W-30 is thicker at operating temperature, which provides a slightly better protective film on engine parts. The thinner 5W-20 may lead to a minor increase in wear. 
• Increased fuel economy: Because 5W-20 is thinner, it requires less energy to pump, which can result in a small improvement in fuel efficiency. 
• Impact on high-performance engines: Some high-performance engines have tight tolerances and are designed for thinner oil. However, putting 5W-20 in an engine that specifies 5W-30 can be problematic for some modern high-compression engines, potentially leading to bearing failure if driven hard, says Quora. 
• Warranty concerns: If your car is under warranty, using the wrong oil could potentially void your warranty in case of a powertrain failure. 

What you should do

• Check your owner's manual: The safest bet is to always use the oil recommended by your car's manufacturer. 
• If the wrong oil was added during an oil change:
  • Modern cars: For most modern cars, this will likely not cause any immediate damage, but you should have the oil changed to the correct weight as soon as possible. 
  • High-performance cars: If you have a high-performance vehicle, change the oil to the recommended weight immediately to avoid potential damage. 
• If you just added a small amount of 5W-20 to an engine that calls for 5W-30: This is generally not an issue. 
  • For most modern cars, you can continue using 5W-30 as recommended in your owner's manual. 
  • However, if you have a high-performance vehicle, check your owner's manual to see if you need to change the oil to 5W-30 immediately. 

What happens if you accidentally put 10w30 instead of 5w30?

Using 10W-30 instead of 5W-30 is generally acceptable for many vehicles, especially in warmer climates or with older engines, as both oils have the same viscosity at operating temperature. However, 5W-30 is recommended for cold climates because its lower "winter" viscosity allows it to flow more easily during cold starts, reducing initial engine wear. Swapping to 10W-30 in a vehicle designed for 5W-30 can lead to slower oil flow and potential damage if it's frequently exposed to temperatures below freezing. 
When it's likely okay

• Warmer climates: If temperatures consistently stay above 0∘F0 raised to the composed with power cap F0∘𝐹 (-18∘Cnegative 18 raised to the composed with power cap C−18∘𝐶), the thicker 10W-30 is less likely to cause problems. 
• Older engines: A slightly thicker oil can sometimes help older, high-mileage engines that might burn oil or have larger internal gaps due to wear. 
• Moderate driving: If you don't frequently drive in extreme cold, the difference will be minimal. 

When to avoid it

• Cold climates: In regions where temperatures frequently drop below freezing, the 10W-30 will be thicker and may not lubricate the engine as quickly on a cold start, which is when most engine wear occurs. 
• Modern engines: Newer vehicles with specific requirements for oil pressure, like those with variable valve timing (VVT), should stick to the manufacturer's recommendation to avoid potential issues. 
• When the owner's manual specifies 5W-30: The safest and best practice is to always use the oil viscosity recommended in your vehicle's owner's manual, as it was specifically chosen for that engine's design. 

This video explains the difference between 5W-30 and 10W-30 motor oils: 53sThe Savvy ProfessorYouTube · Apr 19, 2023
Potential signs of a problem
Tougher cold starts, Ticking or tapping noises after startup, Higher than normal oil pressure reading, and A noticeable drop in fuel economy.