If you’ve ever looked at your receipt after an oil change and wondered, “Did I really need the synthetic stuff?” — you’re not alone.
Choosing between synthetic and conventional oil can feel like guesswork. The prices are different, the labels don’t always help, and depending on who you ask, you’ll get a different answer. This guide breaks it down so you can make the right call for your vehicle and your budget.
What Is Conventional Oil?
Conventional motor oil is made from refined crude oil. It provides basic lubrication to protect your engine’s moving parts from heat and friction.
Benefits:
- Less expensive
- Adequate for older engines and vehicles with low mileage
- Works well under normal driving conditions
Limitations:
- Breaks down faster in extreme temperatures
- Requires more frequent changes
- Doesn’t offer as much protection under stress (like towing or stop-and-go driving)
What Is Synthetic Oil?
Synthetic oil is chemically engineered to perform better than conventional oil. It’s more refined, more stable, and designed to resist breakdown under heat and pressure.
Benefits:
- Longer-lasting performance
- Better protection at high and low temperatures
- Keeps engines cleaner with fewer deposits
- Improves fuel economy in some vehicles
Limitations:
- Costs more per quart
- May not be necessary for every engine type
Key Differences
| Feature | Conventional Oil | Synthetic Oil |
| Price | Lower upfront cost | Higher cost per change |
| Oil Change Frequency | 3,000–5,000 miles | 7,500–10,000 miles |
| Temperature Stability | Breaks down faster | Performs well in cold/hot temps |
| Engine Cleanliness | Leaves more deposits | Cleaner running engine |
| Ideal Use | Older, low-stress engines | High-mileage or performance vehicles |
What About Synthetic Blends?
Synthetic blends are a mix of conventional and synthetic oils. They offer better performance than conventional oil at a lower cost than full synthetic.
They’re a great middle ground if you want some of the benefits of synthetic without the full price tag.
When Should You Use Synthetic Oil?
You should consider synthetic if you:
- Drive in extreme heat or cold
- Do a lot of stop-and-go city driving
- Tow heavy loads
- Own a newer or high-performance vehicle
- Want to extend the time between oil changes
Some vehicles require synthetic oil — especially newer engines with turbochargers or high-performance components. Check your owner’s manual or ask your technician if you’re not sure.
Can You Switch Between the Two?
Yes. If your vehicle doesn’t require synthetic oil, you can safely switch between conventional and synthetic (or blend) without harming your engine. Just don’t mix them in the same oil change unless it’s a blend formulated to do so.
Final Thought: Ask What’s Best for Your Car
Not all engines are the same. At OK Tire Store & Service, we help customers across Minnesota and North Dakota understand what works best for their vehicle, driving habits, and climate. Whether you need a basic oil change or are looking to extend engine life, we’ll walk you through the best options — no upsell pressure.
FAQ: Oil Change Questions
Is synthetic oil worth the extra cost?
It can be. You’ll go longer between oil changes, and it protects your engine better — especially in harsh conditions or newer engines.
Can synthetic oil extend engine life?
Yes. It reduces wear and deposits, which can help your engine last longer if you follow recommended change intervals.
Will synthetic oil void my warranty?
No. As long as the oil meets the specifications in your owner’s manual, it won’t void your warranty — even if it’s not the exact brand your dealer recommends.
Do older cars need synthetic oil?
Not always. Many older engines run just fine on conventional oil unless you’re driving in extreme conditions or the manufacturer recommends synthetic.