How Often Should You Change Engine Oil? Facts, Myths, and Manufacturer Recommendations.

Engine oil is one of the most important fluids in your vehicle. It lubricates, cools, and protects the engine from wear. Despite this, many drivers still wonder: how often should you change engine oil? How many miles should you drive between oil changes, and is it safe to follow “long-life” intervals?

In this article, we explain what really affects oil change frequency, debunk common myths, and show how to tailor the interval to your driving style and engine type.

How Many Miles Between Oil Changes?

The simplest answer is: every 6,000–10,000 miles or once a year, whichever comes first.
This general rule applies to most gasoline engines.

Diesel engines can follow slightly different guidelines. Since diesels produce more soot and contaminants, it’s best to change oil every 10,000–12,000 miles, even if the manufacturer suggests longer intervals. Despite this difference, diesel engines generally require less frequent oil changes than their gasoline counterparts.

Some manufacturers (e.g., BMW, VW, Audi) offer “Long Life” oils, theoretically allowing intervals up to 18,000–20,000 miles. In reality, this works only with regular highway driving in near-perfect conditions.

🔧 Expert tip: If you mostly drive in the city, make short trips, or often start the engine cold, shorten the interval by up to 30%.

What Determines Oil Change Frequency?

Driving Style and Conditions

The way you drive greatly affects oil health.

• City driving – short trips, cold starts, and stop-and-go traffic degrade oil much faster.
• Highway driving – steady speeds and warm temperatures help oil last longer.
• Harsh conditions (towing, mountains, heavy loads) – require more frequent changes.

Type of Engine

Diesel engines are harder on oil due to increased soot and contamination. Gasoline engines run cleaner and heat up faster, so oil lasts a bit longer.

Turbocharged and direct-injection engines also demand more frequent changes because they operate under higher temperatures and pressure.

Oil and Filter Quality

Not all oils are created equal. Cheaper oils lose viscosity quickly and their additive packages break down under heat. Always choose oil that meets your car manufacturer’s specifications, and replace the oil filter every time.

🧰 Pro tip: Even the best oil won’t help if the filter is old and clogged — contaminants may circulate back into the engine, or the flow of oil become insufficient.

Facts and Myths About Engine Oil Changes

“Modern cars don’t need oil changes anymore” – MYTH

All engines contaminate and degrade oil over time. Technology helps, but it can’t eliminate the need for fresh oil.

“If I don’t drive much, I don’t need to change the oil” – MYTH

Oil ages even when the car is parked. Moisture, oxidation, and fuel residues gradually break it down. After about a year, the oil loses much of its protective ability — even with low mileage.

“More expensive oil is always better” – NOT ALWAYS

Price isn’t everything. Compatibility with your engine’s specifications (e.g., ACEA, API, manufacturer approvals) matters far more.

“Long-life oil can last 20,000 miles with no risk” – PARTIAL TRUTH

Yes, but only under ideal conditions. For everyday city driving, it’s safer to shorten the interval to about 12,000–15,000 miles.

What Do Manufacturers Say?

(*** Check manufacturer’s instructions for your specific engine model. )

Most automakers use two types of oil change schedules: fixed and flexible. Here’s a simplified comparison: