Switching to Synthetic Oil After 100K Miles? – Is it Possible or Not 

Switching to Synthetic Oil After 100K Miles?

Vehicles with high mileage are prone to wear and tear. Drivers tend to turn towards synthetic oils under such circumstances. But switching to synthetic oil after 100K miles possible or not? 

That is a massive debate with several controversial myths and opinions. 

No wonder you are utterly confused and oblivious about the matter. But fret not, as you have come to the right article. 

Here we will clear up your confusion and answer your questions about switching to synthetic oil after 100k miles, the possibility, safety, and more. 

Keep reading to learn the reality about the matter and free yourself from incorrect opinions and myths. 

Switching to Synthetic Oil After 100k Miles, Is It Possible? 

Yes, it is possible to switch to synthetic oil after 100k mileage. 

A vehicle traveling 100k miles is a lot of work for the engine and the vehicle’s internal system. 

That means the engine has endured a lot and is exhausted. The chances of the engine wearing off remain high in such instances. 

Logically, at such times drivers will seek out a way to enhance the engine life and boost performance. And the first option that will pop up is switching to synthetic oils from conventional oil. 

But the level of reservation and hesitation will remain high since there is a lot of argument on the possibility. 

We have got the answer for you with a logical approach after much practical research. 

So yes, it is possible, and you can always opt for synthetic oil to enhance performance and endurance. 

What Happens When You Switch to Synthetic Oils? 

Logically and practically, there will be a boost in the performance and endurance of the vehicle. 

To go into detail, synthetic oil will offer many significant advantages that will support high mileage without posing any threats to the engine and other vital internal components. 

Let us look at some advantages you will gain after switching to synthetic oil from conventional oil. 

  • Synthetic oil is thinner than conventional oil. The viscosity index is relatively high. So it coats more quickly and evenly on the surfaces of the components. This can help provide a smooth riding experience despite the mileage levels. 
  • There will be less friction acting. Less friction means less horsepower. And that’s a win. 
  • The vehicle will generate lower amounts of heat compared to it will when used conventional oil. This will enable you to drive more miles safely. 
  • The internal components receive extra protection. Therefore, they are not subjected to damage easily. Their lifespans will be extended, and they will not wear off quickly due to the high mileage. 

That’s a lot of great benefits no one would want to miss. 

Are there Any Disadvantages? 

There is indeed one. But it cannot really be said at a disadvantage synthetic oil has to offer. It can serve as a disadvantage if your vehicle is poorly maintained.

In poorly maintained vehicles, there can be places prone to leaking. As synthetic oils are thinner than conventional oils, they are more likely to leak in such vehicles. 

However, note that it does not leak in every single vehicle. 

If your vehicle is maintained correctly and is run with quality oil, there is nothing to worry about. 

On the contrary, if it is not the case, there is a chance for leakage. 

Is it Safe to Switch to Synthetic Oil? 

Synthetic oil is safe to adapt to if you have good maintenance on your vehicle.

 However, certain things should be given consideration before making a decision. 

Let us see what needs your consideration before switching to synthetic oil after 100k miles. 

  • Seals and the Gaskets 

Check the seals and the gasket of your vehicle. A vehicle prone to leakage will not be compatible with synthetic oils. Moreover, if you have been using conventional oil all your life, it is not a good choice to opt for synthetic oil now. 

Why? Because the synthetic oil will run through all the surfaces and clean up all the deposits from the seals the conventional oil protected before. As the oil is thin in nature, this is unavoidable. 

But it is possible to switch to synthetic oil in this case. If you need to change to one, you can start with a synthetic blend and move to synthetic oil gradually. But remaining with the conventional oil you have always used will keep the engine safe. 

  • Leakage 

As we discussed before, a leaky vehicle can be incompatible with synthetic oil since they are very thin and can spread out evenly. Inspect your car for leak spots and get them repaired before switching to synthetic oil. 

The old sludge and seal formed by the conventional oil will be cleared up after pouring in the synthetic oil. The removal of the sludge can lead to leakage as well. 

Therefore at the beginning, carry out frequent oil changes. As time goes by, you can extend the intervals and settle for oil changes with long intervals. 

  • Gaps and the Oil Texture 

Synthetic oil and conventional oil have different textures. The molecular size of traditional oil is larger and uneven. On the other hand, the molecular size of synthetic oil is smaller and even. 

The gaskets and seals in the vehicle contain tiny holes and pores. When pouring conventional oil, the molecules cannot pass through the holes as they are big enough. So instead, they form sludge and proceed to work.

On the contrary, when you pour synthetic oils, they will move through the holes and pores since they are in molecules. And you end up with potential leaks. 

To avoid that, get your car to a mechanic and have the pores and holes in the gasket and seals taken care of. So there will be no issues when you switch to synthetic oil. 


You can switch to synthetic oil after 100k miles with no doubts if you know the vulnerable points. By this point, you know what to be cautious of.

 Switching to synthetic oil is excellent if your vehicle is under good maintenance and has no issues. If your vehicle has problems, take care of them before switching to synthetic oil. 

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