engine oil myths

Common Engine Oil Myths

In Engine Oil by Magnus Sellén1 Comment

When you have brought your car in for repair, you have probably heard some myths about engine oil from the mechanic.

If you do not know what is true and false, it can ruin your engine. Car models differ, and this means that the way you use engine oil is also different.

Myths are widespread and it is difficult to determine the origin of a myth. But you have to counter the myth with facts.

Common Engine Oil Myths

There are a lot of myths circulating about motor oil. Here is a list of the 12 most common myths, some of which are more common than others.

1. You need to change the oil after 3,000 miles

Most people will have an oil change in their next car service. They probably told you to change the engine oil after 3,000 miles. However, this is not an exact procedure. Vehicle models differ and depending on the engine oil, an oil change can be done after 5,000 to 7,000 miles. You should check your car manual for an oil change or monitor the car’s diagnostic system.

2. You do not need to switch to higher quality oil if the car is running well

Poor quality oils are very harmful to the car’s engine. Poor quality engine oils are contaminated with impurities that affect the lubricating properties of the oil. Over time, you will begin to spend more on repairs and this eventually leads to engine damage.

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Changing to a quality engine oil will not affect your engine. On the contrary, it actually improves it.

3. You need to get new oil when going on a road trip

It is not quite true that you have to change your engine oil ahead of a long journey. If your car has been due for maintenance during this period, it is advisable to change it before you set off. However, if you have done your service recently, you can always change the oil when you come back. When doing so, you must check the oil dipstick level. Top up more oil if it is below the minimum.

4. You need to change the oil if it’s black

The new engine oil has an amber color. However, with continued use, the oil will become contaminated with dirt as it passes through the engine. Engine oil that is black in color is normal and should not be a cause for concern.

5. You can continue using the oil filter after an oil change

engine oil

The oil filter and the engine oil work together. The oil filter helps to keep impurities away from your engine so that the lubricating properties of the oil are maintained. It is recommended to change the oil filter every time you change the oil. Otherwise, your new oil will contaminate more quickly.

6. You cannot switch back after using synthetic oil

Car drivers often choose synthetic oil because of its resistance to high temperatures. It also has excellent cleaning properties. After a while, you may want to change back to your original oil. As long as the viscosity of the oil is the same, you can always switch between the two oils.

You can contact your mechanic to get the best synthetic oil. When synthetic oil was first used, there were many complaints about it causing leaks. When the manufacturer improved the oil, there was a decrease in such cases. However, you will still hear complaints from older car owners.

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7. The “W” letter on engine oil packaging stands for weight

That’s not true. Most people assume that the W means that you have to use it for a certain car/bike weight. The W simply stands for winter.

8. Quality oil leaks in older engines

The myth says that with an older engine you have to expect oil to leak under the engine. This is not true. High-quality engine oil has been tested, and if you find a leak, your seals may be defective.

9. Engine oil is responsible for sludge

Sludge is caused by the accumulation of engine deposits, unburnt fuel, and leaking coolant. High-quality oil cleans the engine of these contaminants and suspends it. If you notice an accumulation of sludge, you may be using poor quality engine oil.

10. You know it’s time to change engine oil through its smell

Engine oil is intended to clean the engine and when it is finished, it turns black. You should change the engine oil at regular intervals according to the oil manufacturer’s instructions. If the oil is not changed, the effectiveness of the oil in lubricating and cleaning the engine will be reduced.

11. You need to use detergent oil to break in a new engine

This is not a myth. The manufacturers suggest using detergent oil to run in a new engine. The reason for this is the new engine design and modern oil formulation.

12. Thicker engine oil is the best

That’s not true. Thinner oil offers the best viscosity and is best suited for use in engines. It provides better lubrication and helps to remove contaminants from the engine. Thinner oil reduces friction between moving parts and is efficient because less energy is needed to pump it through the engine parts.


Myths are created by humans, but they often have no factual basis. Many people do not understand how engine interior parts work and rely on the knowledge of their mechanics when changing car parts. Engine oil plays an important role in keeping all engine parts lubricated and reducing friction.

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A widespread myth is the mileage required to change engine oil. Some will argue that it should be 3,000 miles, others 7,000 miles, but you should change the engine oil according to the manufacturer’s instructions. Engine oil turns dark after use. This is due to the accumulation of sludge. This does not mean that the oil is bad, but it does play its part. It is not a must to change the engine oil every time you drive a long distance.

If your car is due a service, change it, but if you have already done so, your car is ready to go. However, carry out a service check before traveling. Check that all car fluids are in good condition. This includes the coolant, brake fluid, and engine oil. Knowing when to change your engine oil will help keep your car running optimally.

The right engine oil protects all moving parts from friction and overheating. Always use the recommended low viscosity engine oil.

12 Common Engine Oil MYTHS

1 thought on “ Common Engine Oil Myths ”

  1. I purchased many liter bottles of 5w30 Castorol synthetic motor oil in a bankrupsy [ cheap ! ].
    Does this oil have a shelf life?

  2. Due to very high demand and a high amount of comments, you might have trouble getting your comment answered by me. If you want to get fast answers from a certified automotive technician you should ask your questions here: Ask A Mechanic

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