Synthetic vs Conventional Oil: Which Does Your Car Need?
Use the oil type and viscosity your owner's manual specifies. Full synthetic oil resists breaking down at high temperatures, flows better when cold and allows longer change intervals, which is why many newer engines, especially turbocharged ones, require it. Conventional oil costs less and is fine for engines designed for it. A synthetic blend sits in between.
Comparison
| Conventional | Synthetic blend | Full synthetic | |
|---|---|---|---|
| Cost | Lowest | Middle | Highest |
| High-heat protection | Good | Better | Best |
| Cold-start flow | Good | Better | Best |
| Typical interval | Shorter | Medium | Longest |
| Required by many turbo and newer engines | No | Sometimes | Often |
What to look for on the bottle
- Viscosity, such as 0W-20 or 5W-30, matching the manual.
- API service rating (the "donut" symbol) and, where the manual requires it, an ILSAC or manufacturer approval such as dexos.
- European specifications (for example VW 504 00 or MB 229.5) for cars that require them.
Book an oil change
The listed price for a synthetic oil change on AppointAuto is $69.99. Each shop sets its own final price.
Frequently asked questions
What does 5W-30 mean?
The first number with W (for winter) shows how easily the oil flows when cold; lower is thinner when cold. The second number is the viscosity at normal operating temperature. Use the grade in your manual.
Can I switch from conventional to synthetic oil?
Yes. Synthetic oil is compatible with engines designed for conventional oil, as long as it is the correct viscosity and specification. Switching back is also fine if the manual allows conventional oil.
Can I mix synthetic and conventional oil?
Yes, for topping up. They are compatible; you just lose some of the full synthetic's benefits until the next change.
Does synthetic oil cause leaks in older cars?
Synthetic oil does not create leaks, but it can reveal worn seals that were already close to leaking. Use a high-mileage oil if the engine has many miles.
Related guides
- How Often Should You Change Your Oil? The 3,000-Mile Myth — Most modern cars go 5,000 to 10,000 miles between oil changes. How to find your real interval, what counts as severe driving, and signs the oil needs changing.
- Your Auto Repair Rights in California: Estimates, Invoices and Old Parts — California shops must be BAR-registered, give a written estimate, get your OK before exceeding it and return replaced parts on request.
- How Often Should You Rotate Your Tires? — Most cars need a tire rotation every 5,000 to 7,500 miles. Rotation patterns for front, rear and all-wheel drive, and why rotating saves money.