You’re about to change your car’s oil, and then you realize that you only have part synthetic and part conventional oil. You start wondering: “Can I just mix them together?”.
This is a common situation for many car owners. Sometimes, you run low on oil and only have conventional oil on hand when your engine is filled with synthetic. Other times, you’re looking for ways to save money but still want some benefits of synthetic oil. So, does mixing them actually harm your engine? And if you do, what happens inside your engine?
Read on as I’ll provide comprehensive answers to theses questions in the article.
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Can You Mix Synthetic and Conventional Oil?
Yes, you can mix synthetic and conventional oil, but it’s not the best idea for your engine’s long-term health. Your car won’t suddenly stop working if you mix them, and in an emergency; like if you’re low on oil and only have a different type available, it’s completely fine to top up with what you have.
However, understand that synthetic oil is engineered to last longer, resist high temperatures, and keep your engine cleaner. Conventional oil, on the other hand, breaks down faster and can leave more sludge behind. When you mix them, you weaken the benefits of synthetic oil, reducing its ability to protect your engine over time.
It is more like mixing premium and regular gasoline. Your car will still run, but it won’t perform as well as if you stuck with one type. If you accidentally mix oils, don’t panic, just plan for an oil change sooner than usual. If you’re unsure how often to change your synthetic motor oil, read this article: How Often Should You Change Synthetic Motor Oil?
Check out some of the best synthetic motor oil below;
If you want a balanced option without the risks of mixing, consider using synthetic blend oil, which is specifically formulated to combine both types without sacrificing performance. This way, you get some of the advantages of synthetic oil while keeping costs lower.
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Frequently Asked Questions
Having understood the details about mixing synthetic or conventional oil, you might still have some lingering questions. Here are answers to some of the most frequently asked questions about blending these types of oil.
Does Mixing Synthetic and Conventional Oil Damage Your Engine?
Mixing synthetic and conventional oil won’t destroy your engine, but it’s not ideal. Modern engines are designed to work best with a specific type of oil. When you mix the two, you dilute the benefits of synthetic oil.
Synthetic oil provides better protection against heat and sludge, while conventional oil breaks down faster. If you mix them once in an emergency, your engine will survive, but it’s better to stick to one type for long-term performance.
What Happens When You Mix Synthetic and Conventional Oil?
When you mix synthetic and conventional oil, nothing dramatic happens right away, your engine won’t suddenly break down or stop running. The two oils blend without causing a harmful chemical reaction.
However, the mixture won’t offer the same performance benefits. Synthetic oil perform better under extreme temperatures, reduce friction, and prevent sludge buildup, while conventional oil breaks down faster and doesn’t offer the same level of protection. When you mix them, you dilute the benefits of synthetic oil, making your engine more vulnerable to wear and tear over time.
If you mix oils once in an emergency, it’s fine; just schedule an oil change sooner than usual to restore proper protection. But if you keep mixing them regularly, your engine may not get the full benefits of either type, leading to more frequent maintenance and possibly shorter engine life.
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What’s the Best Alternative to Mixing Oils?
Instead of mixing, the best alternative is to use a synthetic blend oil, which is a pre-mixed combination of synthetic and conventional oil. These blends are formulated to work together, ensuring better protection and performance than mixing separate oils yourself. Many manufacturers already recommend synthetic blends as a middle ground.
Is It Ever Okay to Mix Synthetic and Conventional Oil?
Yes, but only if necessary. If you’re low on oil and the only option available is different from what’s in your engine, adding some is better than running the engine dry. However, it’s best to change your oil completely at your next service to maintain the right balance of additives and viscosity.
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How Often Should You Change Oil If You’ve Mixed It?
If you’ve mixed synthetic and conventional oil, you’ll need to change it sooner than usual because the weaker oil in the mix (conventional oil) will break down faster. Normally, full synthetic oil lasts around 7,500 to 10,000 miles, while conventional oil needs a change at 3,000 to 5,000 miles.
When combined, the overall performance leans toward the shorter end of that range. So, if your car usually runs on synthetic oil, but you’ve added conventional in a pinch, aim to change it within 5,000 miles or sooner to prevent sludge buildup and keep your engine running smoothly. Meanwhile, always follow your owner’s manual for the safest interval.
Should You Flush the Engine After Mixing Oils?
Flushing your engine after mixing synthetic and conventional oil usually isn’t necessary as long as the oils were of good quality and your engine was in decent shape. Modern oils are made to be compatible, so mixing them once won’t cause immediate harm. If you’ve only topped off your oil in an emergency, you can simply switch back to your preferred type at your next oil change.
However, if you’ve been mixing oils repeatedly or using low-quality conventional oil, a flush might help clear out sludge and old additives that could be affecting your engine’s performance.
Does Mixing Oils Affect Your Warranty?
It depends on the manufacturer. Some warranties specify that using the recommended oil type is required to keep the warranty valid. If your car is still under warranty, check the manual before using a mixed oil blend. If unsure, stick with one type of oil to avoid complications.
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Conclusion
While mixing synthetic and conventional oil isn’t catastrophic, it’s not recommended for long-term use. It reduces performance, shortens oil life, and might not provide the protection your engine needs. If you ever have to mix oils, plan to change your oil sooner rather than later. For the best engine performance, always use the recommended oil type and stick to a consistent maintenance schedule.