Yes, you can absolutely switch to synthetic oil after using conventional oil in your car. It's a safe and often beneficial upgrade. Modern synthetic oils are engineered to be fully compatible with conventional oil residues. The switch won't harm your engine and typically provides better protection, improves performance, and can even extend the time between oil changes.
The primary advantage of synthetic oil lies in its chemical structure. While conventional oil is refined from crude oil, synthetic oil is chemically engineered to create more uniform molecules. This results in superior performance in several key areas:
- Engine Wear Protection: Synthetic oil flows more easily at low temperatures, providing critical lubrication to engine parts faster upon a cold start—when most engine wear occurs. It also maintains its protective viscosity better at high temperatures under heavy load.
- Sludge Prevention: Synthetic oil is more resistant to thermal breakdown, which is a primary cause of sludge and deposit formation inside the engine. This helps keep critical components clean for longer.
- Longevity: Because it's more stable, synthetic oil can often be used for longer intervals than conventional oil, as recommended by your vehicle's manufacturer.
Here’s a quick comparison of the key benefits:
| Advantage | Conventional Oil | Synthetic Oil |
|---|
| Cold-Start Protection | Slower to circulate | Flows quickly at low temps |
| High-Temperature Stability | Can thin out and break down | Maintains protective film strength |
| Engine Cleanliness | More prone to sludge formation | Excellent resistance to deposits |
| Recommended Change Intervals | Typically 3,000-5,000 miles | Often 5,000-10,000+ miles |
| Engine Wear Reduction | Good | Superior |
Before switching, it's always best to consult your owner's manual. Some high-mileage vehicles might benefit from a specific high-mileage synthetic blend formulated with conditioners for older engine seals. There's no need for a special engine flush; just drain the conventional oil, replace the filter, and fill with the synthetic oil of your choice.
