How often should you change engine oil?
Engine oil performs several functions in a car, including lubricating engine components, reducing friction, and minimizing unnecessary loss of power.
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Keeping your engine well lubricated will keep it in good working order and reduce the possibility of unexpected failure. While changing your engine oil is relatively easy, our guide will help you understand how often you should change the engine oil, and what type of oil is best for your vehicle.
Oil change frequency
In the past, carmakers insisted that owners change their engine oil every 3,000 to 5,000 miles (5,000-8,000 km). However, as oil chemistry and engine technology advanced, oil change intervals became longer.
While modern engines require less frequent oil changes, that doesn’t mean you should always follow the car maintenance schedule when changing oil. Manufacturers recommend oil change intervals based on unrealistic driving conditions, helping reduce theoretical maintenance costs, but decreasing your engine’s longevity.
The most effective method of establishing an oil change schedule is to consider your daily driving conditions. And in fact, most modern vehicles are equipped with an oil life monitoring system, automatically displaying a notification when your car maintenance is due. More advanced systems show the “change your oil” message based not only on mileage or oil level but on actual conditions affecting the oil’s quality.
Why is changing the oil important?
Numerous moving elements in engines need to be properly maintained in order to prevent damage.
Important engine components eventually become polluted with dirt and other particles over time. To eliminate the extra filth that accumulates in the engine, replacing the oil after a set period of time is crucial.
If the longevity of your car’s engine is a top priority, the following reasons should be enough to convince you to change the oil on time.
An oil change improves fuel economy
Oil and dirt buildup inside the engine makes it work harder to generate power, consuming more fuel. Appropriate maintenance reduces unnecessary strain on your engine, extending its life and improving fuel efficiency.
Cools down engine components
Engine oil reduces friction within the engine. When engine oil loses its lubricating characteristics, friction between important engine components increases, causing critical components to wear more quickly.
Helps to notice unrelated issues
A visit to the workshop is a great way to inspect a vehicle’s health. A quick vehicle inspection can reveal hidden problems that could later contribute to a hefty repair bill.
Types of motor oil for your vehicle
Each type of motor oil has a unique set of characteristics that can improve the performance of your car. Understanding the role of motor oil might help you decide which type is best for your vehicle.
Traditional (mineral) motor oils
Due to their thickness in various conditions, traditional (mineral) oils are commonly used in classic cars or vehicles with a higher mileage.
Semi-synthetic motor oils
Semi-synthetic oils are a mixture of fully synthetic and traditional (mineral) oils designed to keep costs low while improving the lubrication properties of mineral oil.
Synthetic motor oil
Most modern vehicles require synthetic oil because of its ability to protect the engine from wear, oxidation, and corrosion.
What is oil viscosity?
Oil viscosity refers to how well a lubricant flows at a given temperature. Thin oils have lower viscosity and flow more easily at low temperatures than thicker oils with higher viscosity. Furthermore, thin oils reduce engine friction and help engines start more easily in cold weather. Meanwhile, thick oils are better at maintaining oil pressure in high temperatures and loads.
SAE (Society of Automotive Engineers) distinguishes 14 viscosity grades – 6 winter grades with a number before the letter W (0W, 5W, 10W, 15W, 20W, 25W) and 8 summer grades with a number after the letter W (W8, W12, W16, W20, W30, W40, W50, W60).
Winter grade oils are thinner, thus having a better flow rate at lower temperatures. Summer grade oils indicate the oil’s viscosity at high temperatures. The higher the number, the bigger the viscosity, resulting in better engine protection in higher temperatures.
Engine oil quality classifications
There are 2 engine oil quality classifications: API (American Petroleum Institute) and ACEA (Association des constructeurs Européens d’Automobiles).
The classification adopted in the United States (API) is divided into 2 groups: “S” for petrol-driven engines and “C” for diesel engines.
In Europe, applications for motor oils are divided into 4 groups: “A” for petrol-powered engines, “B” for diesel engines, “C” for diesel engines with particulate filter compatibility, and “E” for commercial diesel vehicles.
Oil change frequency and driving conditions
Carmakers determine oil change frequency by several criteria strongly related to driving conditions.
You should only utilize the extraordinarily long engine oil change intervals (15,000-20,000 miles or 24,000-32,000 km) in vehicles operated under normal driving conditions. This applies to vehicles typically driven on highways and other areas where engines aren’t subjected to excessive loads.
The following driving conditions are meant as a hint to change your engine oil every 5,000 miles (8,000 km):
- Frequent, extended idling, such as stop-and-go driving in congested areas.
- Towing a trailer or boat or hauling bulky items on a roof rack.
- Driving on dusty, gravel, or dirt roads.
- Driving with frequent elevation changes.
Oil change frequency and mileage
Oil change intervals based on annual mileage often makes a lot of sense and reduce maintenance complexity.
If a mileage-based oil change schedule appears appropriate, be prepared to change a car’s oil every 10,000 miles (16,000 km) or once a year – whichever comes first.
Oil change intervals for older cars
Given the advancements made in internal combustion engine technology during the last 50 years, the definition of an old car might be too broad.
The frequency of oil changes for older vehicles should be based on the production date:
- Cars built since 1990: 6,000 to 10,000 miles.
- Cars built since 1970: 4,000 to 6,000 miles.
- Cars manufactured before 1970: every 6 to 12 months or every 3,000 miles.
Oil change cost
The average engine oil change takes just 30 to 45 minutes, making a scheduled oil change one of the least demanding car maintenance tasks.
While engine oil could be changed quite swiftly, the oil change cost depends on a rather long list of factors.
Oil change cost factors
The most significant oil change cost factor is whether you plan to carry out the work yourself or have it done in a workshop. However, also take into account the following cost factors:
- Engine size
- The engine oil type
- The required engine oil viscosity
- The oil manufacturer
- The amount of engine oil required
How do I know when my oil needs changing?
The oil light on the dashboard is the most obvious clue that your car’s engine needs an oil change. Otherwise, you should follow a mileage-based schedule.
Is it OK to change oil once a year?
It depends on your yearly mileage. If your annual mileage is no more than 15,000 miles (24,000 km), it’s OK to change your oil once a year.
Should I use synthetic or conventional oil?
You should always follow the manufacturer’s recommendations because every engine should use specific grade oil to work at its most efficient.
What is long-life oil?
Long-life engine oil should extend oil change intervals. However, you should use this oil only if you’re doing a lot of motorway miles and avoiding the usual stop-and-go traffic.
Do I really need to change my oil filter?
Yes. You should replace the oil filter every time you carry out an oil change. It doesn’t matter if your car has a petrol or diesel engine.