Conventional vs. Synthetic Oil: Which Does Your Engine Need?

Motor oil has one job that matters more than any other: keep metal from touching metal. All three tiers do that. The difference is how long they do it well, and under what conditions.

Conventional ($49.99)

Refined from crude oil with additive packages. Perfectly good for older, non-turbo engines driven normally, with changes every 3,000–5,000 miles. If your owner's manual doesn't require synthetic and you drive a 2010 sedan to work and back, this is a fine choice.

Semi-Synthetic / Synthetic Blend ($64.99)

A mix of conventional and synthetic base oils. Better resistance to heat breakdown and sludge, longer intervals (typically 5,000–7,500 miles), and a noticeable step up for higher-mileage engines or vehicles that sit in Birmingham traffic every day. This is our most popular tier for good reason.

Advanced Full Synthetic ($94.99)

Engineered base oils with the most stable molecules. Required by most modern engines — especially turbocharged, direct-injection, and European vehicles — and the right choice for towing, extreme heat, or long highway trips. Intervals of 7,500–10,000 miles are common.

How to choose

• Check the oil cap or owner's manual. If it says 'synthetic required,' that's not optional.
• Turbo? Full synthetic. Turbos run extremely hot and cook conventional oil.
• Over 100,000 miles on a non-turbo engine? A blend is often the sweet spot.
• Short trips, lots of idling, or extreme heat? Move up a tier — those conditions are harder on oil than highway miles.