Can You Use Synthetic Oil After Using Conventional?

Is It Safe to Switch from Conventional to Synthetic Oil?

Yes, you can switch to synthetic oil after using conventional oil without any issues. Modern engines and synthetic oils are fully compatible, and no engine flush or special preparation is required.

Benefits of Switching to Synthetic Oil

✅ Better Engine Protection – Synthetic oil reduces wear and deposits.
✅ Improved Performance in Extreme Temperatures – Flows better in cold weather and resists breakdown in high heat.
✅ Longer Oil Change Intervals – Synthetic oil lasts longer than conventional oil.
✅ Better Fuel Efficiency – Reduces engine friction for smoother operation.

Will Switching to Synthetic Oil Cause Any Problems?

🔹 Older Engines with Worn Seals – Some high-mileage engines may develop small leaks if they already had weak seals.
🔹 If Engine Deposits Are Loosened – Synthetic oil cleans better, which can sometimes dislodge old sludge, but this is rare.
🔹 If You Have a Very High-Mileage Engine – If an engine has always used conventional oil for 100,000+ miles, consider using high-mileage synthetic oil.

How to Switch from Conventional to Synthetic Oil

1️⃣ Check Your Owner’s Manual – Most modern cars support synthetic oil.
2️⃣ Drain the Old Conventional Oil – Perform a standard oil change.
3️⃣ Use a Synthetic Oil Compatible with Your Engine – Match the recommended viscosity (e.g., 5W-30, 0W-20).
4️⃣ Replace the Oil Filter – A fresh filter ensures clean oil circulation.
5️⃣ Drive Normally – No special steps or flushing are required.

Can You Mix Synthetic and Conventional Oil?

Yes, you can mix them, but it’s not recommended. While mixing won’t harm the engine, it reduces the benefits of synthetic oil, such as extended durability and better protection.

Final Thoughts

Yes, you can switch from conventional to synthetic oil at any time, and doing so improves engine longevity and performance. Just ensure you use the correct viscosity and a high-quality oil filter.

FAQs

1. Will switching to synthetic oil cause leaks?

No, but if the engine already has worn seals, synthetic oil may expose minor leaks that conventional oil masked.

2. Can I go back to conventional oil after using synthetic?

Yes, but you won’t get the same benefits as synthetic oil.

3. Do I need to flush my engine before switching to synthetic?

No, just perform a regular oil change and filter replacement.

4. How often should I change synthetic oil?

Most cars can go 7,500–15,000 miles, depending on the oil type and driving conditions.

5. Is synthetic oil worth the cost?

Yes! It lasts longer, protects better, and improves engine efficiency compared to conventional oil.