When to change engine oil in a car

Basics of engine oil change in a car:

Most car owners are aware that changing the engine oil is one of the most important parts of maintaining the car. Engine oil is supposed to protect and lubricate the engine, keeping it in good form. However, over time, engine oil can break down or accumulate contaminants of its own, hampering its functioning and putting the engine at risk. It is therefore necessary to change the engine oil in your car every once in a while.

The question of when to change engine oil in your car is a complicated one. As a rule of thumb, car owners are advised to change their engine oil anytime from 5,000 kms to 30,000 kms. This is because engine oil change intervals can vary a lot, depending on a number of factors. Some factors that affect the change interval are:

  • Design of engine
  • Model and make of the car
  • Age of the car
  • Quality and type of engine oil used
  • Grade of engine oil used
  • Type of fuel i.e. petrol or diesel
  • Driving style
  • Frequency of long drives
  • Traffic and condition of roads 

It is thus clear that there is no one change interval that is applicable to all cars. The best way to determine how often you need to change your engine oil is through understanding the make and needs of your car. Car owners should examine the owner’s manual to find out what type of oil their engine needs and how often it needs to be changed. Furthermore, you can consult with local mechanics and dealerships to understand what oil change intervals suit the needs of your car, given the circumstances of its usage. 

Symptoms that engine oil needs to be changed:

While the engine oil change interval differs a lot based on the factors mentioned before, there are certain signs that you need to look out for which will indicate that your oil needs to be changed. Here are some things to be aware of:

  1. If the ‘Check engine’ or ‘Oil change’ light in the dashboard of your car is lit up or blinking, that means it is time for an oil change as soon as possible.
  2. When oil is unable to lubricate the engine well, it leads to the engine making metallic noises or load grating sounds. If you hear such noises from your car, then get the engine oil changed.
  3. Fresh engine oil is generally golden or amber and is translucent in consistency. If you notice that your oil is dark brown or black in colour and is cloudy or filled with grimy particles, then it is time to get your oil changed. 
  4. If you smell oil inside the car, it can indicate an oil leak. Furthermore, if you smell exhaust inside, it shows engine overheating, which is also caused by old engine oil. These smells mean that you need to get your oil checked.

Engine oil change interval based on type of fuel:

The amount of times you need to get your oil changed depends a lot on the fuel your car runs on i..e whether it is a petrol car or a diesel one. Petrol cars generally need oil changes after every 10,000 kms to 15,000 kms, under normal circumstances. On the other hand, if you own a diesel car, you would need more frequent oil changes. A diesel car requires engine oil to be changed every 7,000 kms or at least once or twice a year

Engine oil change interval based on type of engine oil:

There are three main types of engine oil: Conventional or mineral oil, semi-synthetic oil and synthetic oil. All these are refined to different degrees and thus have different change intervals. Generally, synthetic oil lasts the longest since it is the most advanced. Semi-synthetic comes second, while conventional oil needs to be changed most frequently.

Since conventional oil is the crudest, it gets dirty faster and can also break down easily. It is recommended that conventional oil be changed every 5,000 kms.

Semi-synthetic oil is a blend of conventional and synthetic oil. It is a lot more refined than conventional oil and therefore lasts a bit longer. It is recommended that you change semi-synthetic oil after 7,500 kms to 10,000 kms.

Lastly, fully synthetic oil is the most refined one and therefore does not need to be changed very often. You can change synthetic oil every 10,000 kms to 20,000 kms. 

Engine oil change interval based on usage:

The circumstances in which you drive your car and your driving style also affects the engine oil change interval. For example, if you are a rough driver, accelerating or braking suddenly, then it will put more pressure on the engine, causing you to need oil changes more often, as compared to more moderate drivers.

Furthermore, if you drive on dusty roads, off-roading trails, pothole-filled streets and streets with heavy traffic, it causes your engine oil to work extra-hard to keep the engine protected well. This is why you would need to change oil more frequently. On the other hand, if you drive on smooth, traffic-free roads, then your oil will last longer. 


The oil change interval for your car depends on a number of factors. Therefore, there is no one fixed change interval that is applicable to all. In fact, change intervals can range from 5,000 kms to 30,000 kms. Car owners should study the owner’s manual and consult with local mechanics to understand how often they must change their engine oil. Furthermore, they should keep an eye on their car and look out for symptoms that the oil needs to be changed. 



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