Synthetic vs conventional oil

If your owner's manual or the oil filler cap says synthetic, use synthetic. That is not an upsell. The engine was designed and tested on it, and your warranty can depend on using oil that meets the spec.

If the manual allows conventional oil, synthetic still protects better, especially in heat and stop-and-go traffic. Whether the difference is worth it depends on the car, its age, and how you drive it.

When you come in, we look up what your exact engine calls for, tell you plainly, and let you decide. You should never have to guess what went into your engine.

Conventional oil is refined from crude oil. Its molecules come in many sizes and shapes. That works fine in plenty of engines, but it thins out and breaks down faster under high heat.

Full synthetic oil is built to be much more uniform. It flows better when the engine is cold, holds its thickness better when the engine is hot, and resists turning into sludge. Synthetic blend is a mix of the two, and it lands somewhere in the middle on protection.

The numbers, like 0W-20 or 5W-30, are the viscosity grade. The first number with the W tells you how the oil flows cold. The second number tells you how thick it stays at operating temperature. Use the grade your manual lists. Thicker is not better in a modern engine, and the wrong grade can set off warning lights on engines with variable valve timing.

Many newer engines are small, turbocharged, and direct injected, built with tight tolerances and designed to run on very thin oil like 0W-20 or 0W-16. Those thin grades are generally only made as synthetic.

A turbocharger spins extremely fast and gets very hot. Oil that cooks inside it leaves hard deposits that can block the tiny oil passages and starve the turbo. Direct injection engines can also suffer from a problem called low-speed pre-ignition, a kind of violent knock at low speed. The newest oil standards were written partly to prevent it.

That is why the approval on the label matters as much as the word synthetic. Look for the industry certification marks and any maker-specific specification listed in your manual. An oil without the right approval is not a savings if it costs you a turbo.

Most owner's manuals list two schedules, normal and severe. Severe usually covers extreme heat, heavy stop-and-go traffic, short trips, lots of idling, and towing. For most people here, that is just a regular week.

Heat and idling break oil down faster. An engine sitting in traffic with the A/C on is working hard while the car is barely moving, and the oil keeps getting hotter without much airflow to cool it.

Short trips hurt in a different way. The engine never gets hot enough, long enough, to boil off the moisture and fuel that collect in the oil. In our humidity, that moisture adds up and helps form sludge.

If you drive for rideshare or delivery, sit in traffic every day, idle for work, or tow, follow the severe schedule or the oil life monitor, whichever comes first. Do not stretch the change just because the oil is synthetic.

Follow the oil life monitor if your car has one, or the interval in your manual for the way you actually drive. The old habit of every 3,000 miles comes from older engines and older oils, and many modern cars can safely go longer. Going longer only works if you also keep an eye on the level.

Check the dipstick once a month, on level ground, with the engine off for a few minutes. Some engines use a little oil between changes, and that can be normal up to a point. Running low is how engines get hurt, no matter how good the oil is.

Time counts as much as miles. Oil ages even when the car sits. If you barely drive, change it at least as often as the time limit your manual lists, even if the mileage is low.

You can switch from conventional to synthetic at any oil change. The old story that synthetic causes leaks mostly comes from engines with already worn seals. Synthetic does not create a leak, although its cleaning action can reveal one that was already there.

Topping off with a different brand or type in a pinch is fine. Getting the level back up matters much more than matching the bottle. At the next change, go back to the right oil.

High mileage oils add seal conditioners that can help older engines that seep or burn a little oil. They are not magic, but on the right car they are worth a try. Oil additives sold in a bottle, on the other hand, are rarely needed with a quality oil.

Hybrids need a special note. The gas engine starts and stops constantly and often runs cooler than a regular engine, which lets moisture and fuel build up in the oil. Many hybrids call for very thin synthetic. Use exactly what the manual says, and do not skip changes just because the engine runs less.

When we change your oil, we write the oil type, the viscosity grade, the filter, and the next due date or mileage on your record. Next time, nobody has to guess, and you have proof of maintenance if you ever need it for a warranty claim or a sale.