Why Can’t You Go Back to Regular Oil After Using Synthetic?

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Why Can't You Go Back to Regular Oil After Synthetic?


Technically, it’s possible to switch from synthetic oil to conventional oil. However, doing so will result in performance degradation and reduce the engine’s protection against sludge and other contaminations.

The engine oil is a critical component for any internal combustion engine, as it’s responsible for lubricating its internal parts and protecting them against sludge.

Without this oil, the engine’s internal parts would wear down due to overheating and friction (while making contact with each other) and would be damaged prematurely.

Conventional and synthetic oils are two of the main types of engine oils used in vehicles these days.

While conventional oil is cheap, it doesn’t perform well in extreme temperatures and requires frequent oil changes.

On the other hand, synthetic oil doesn’t change its viscosity even in harsh conditions and lasts longer than conventional oil. But it’s also significantly expensive.

Why Can’t You Go Back to Regular Oil After Synthetic?

There’s a popular myth that you can’t switch back to regular oil after using synthetic oil, as doing so would result in oil leaks.

In reality, there’s no harm in switching between regular and synthetic oil, no matter how often you do it.

I believe this myth mainly exists due to another misconception that regular and synthetic oils can’t be mixed, as doing so would harm the engine. And since there’s a risk of them mixing when you’re switching back to conventional (as a small amount of oil remains in the pan), you shouldn’t do it.

This is completely wrong because you CAN mix regular and synthetic oil without any issue (or even synthetic blend and synthetic oil, for that matter) as long as both have the same weight/viscosity.

That being said, there’s another aspect of this discussion: should you switch back to regular oil after using synthetic?

As synthetical oil is superior to conventional oil in every aspect, you’ll have less performance, more sludge formation, and less mileage after switching to regular oil.

Therefore, it makes little sense to switch back unless you need oil replacement urgently and synthetic oil is not available.

Common Synthetic Oil-Related Myths

Apart from the one we discussed above, there are a few other myths related to synthetic oils that many people still believe in.

It Causes Oil Leaks

The first misconception about synthetic oils is that they sometimes get leaked out of the engine.

While it’s partially true, as they can pass through small openings inside the engine due to superior flow characteristics, it mostly happens when the engine has damaged or worn-out seals and gaskets.

Therefore, the issue is not with the oil but with the engine. The oil is only exacerbating the pre-existing issue.

It’s Not Suitable For Older Vehicles

Many car owners believe that synthetic oils are only suitable for newer vehicles.

In reality, switching to synthetic oil can benefit older vehicles (even if the mileage is 100K+) as it gives better lubrication and protection to the engine, potentially extending its lifespan.

It will Void my Vehicle Warranty

Like other myths, this one is also not true.

The synthetic oil will not void your vehicle’s warranty as long as it has the viscosity specified by the vehicle manufacturer.

It’s Not Suitable In Warmer Climates

Many people think that synthetic oils perform well in cold weather but get too thin in warmer conditions.

In reality, though, these oils are designed to work in hot weather as efficiently as in cold weather.

It’s Expensive

While it’s true that synthetic oils are costly compared to their regular counterparts, this factor gets slightly offset once you consider the fewer oil changes you require with the former.

As synthetic oil is more resistant to heat and breaks down less than regular oil, it can provide lubrication to the engine parts for a more extended period.

This, in turn, allows you to change the oil less frequently and save money.

Another way synthetic oil can help you save money is the extra protection it provides to the engine. This additional protection reduces wear and tear on the engine parts, extending its overall lifespan.

Frequently Asked Questions

What are the Advantages of Using Synthetic Oil Instead of Regular Oil?

Some of the main advantages of synthetic oil are less engine wear during cold starts, lesser sludge formation, and better fuel economy.

How Long Can You Go After Synthetic Oil Change?

You should change synthetic oil after every 7500-15000 miles. But that is a rough estimate, as this limit will depend on your vehicle and driving conditions. Check your vehicle’s owner’s manual for accurate information.

Does Synthetic Oil Last Longer Than Regular Oil?

Yes, the full synthetic oil lasts longer than the conventional oil – thanks to consistent molecular structure, better thermal stability, and additives.

When Should You Not Use Full Synthetic Oil?

If you have an older vehicle and have always used conventional oil, switching to synthetic oil might not be ideal.

What Happens if You Put Conventional Oil in a Car That Requires Synthetic Oil?

Putting regular oil in a vehicle that requires synthetic oil will result in increased engine wear, reduced performance, and extra sludge formation over time.

Andy is an avid car enthusiast with over 5 years of experience in DIYing auto maintenance. He founded AutoProblemz to share his knowledge and expertise with others through writing. His aim is to cut through jargon and help you make the right decisions for your vehicles.

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