Depending on who you ask, the question of how often you should change your Oil will yield different answers. Car manufacturers often recommend about 5000 to 7500 miles, while your local oil shop may have you come in every Tuesday for an oil change.
It used to be that a 3000 mile (4,828 kilometers) interval was recommended, but today, most modern cars do just fine beyond that limit. And that brings us to the first caveat. Older cars from the 1990s and earlier were designed to run on the lubricants available back then.
Therefore older cars should stick to the 3000-mile recommendation or what the owner’s manual suggests.
Putting synthetic oil in very old cars that have not been retrofitted with modern materials can have unintended consequences on the engine’s performance and durability. But that’s a special case because most motorists today aren’t running on clunkers. Let’s start with why the intervals are not given in just mileage but also time.
What does Time have to do with it?
Total Oil says that if stored in optimal conditions, motor oil will remain stable for an extended period though they recommend using it within two years for optimal performance. Over time oil will degrade, becoming less viscous and less effective at lubricating the engine.
If the Oil degrades too much, sludge can form in the engine and block the flow of Oil. A recipe for disaster. To counteract this, synthetic Oil is designed to degrade at a slower rate but is more expensive.
Good synthetic oils will last 10,000 to 15,000 miles before needing a change or approximately six months.
So even if you rarely use your car, an oil change every six months is recommended just to be on the safe side. The Auto Care Guide: When to Get an Oil Change provides a more comprehensive insight into proactive and reactive oil change habits and the danger signs you need to watch out for.
The other main concern is your driving routine:
Driving short trips (less than 20 minutes) does not do good things for the long-term health of your engine. The engine works the hardest from a cold start, which increases wear and tear.
Short trips mean that you likely aren’t reaching the high speeds necessary to get the engine hot enough to burn off condensation in the engine. Moisture buildup causes the Oil to degrade faster and prevents it from properly lubricating the engine.
Therefore, if you’re the type of driver to make short trips (10 miles/16 kilometers), then frequent oil changes of more than 3000 miles will help reduce the damage to your engine. A shift to synthetic Oil will help because the Oil will burn at a lower temperature and flow better than standard engine oil.
Another good candidate for synthetic engine oil is those towing or hauling heavy goods and also those who live in extremely cold or warm climates.
If you have a fairly new car and frequently drive for long distances (over 20 minutes) and at high speeds, then you should consider lengthening the intervals between oil changes. Typically, twice a year is a good bet, but the golden rule is to do as the car manufacturer says.