20w50 vs 10w40

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One engine oil cannot be used for vehicle engines forever. This is because they need a change over time, depending upon the age of the engine.

Manufacturers also mix and blend different base oils and additives to ensure that an engine gets the best lubricant oil. Therefore, you should know that there is no single formula to meet the requirement of all engines.

Hence, different oil types exist in the market based on their functionality and specifications like viscosity, thickness, the weight of the oil, etc.

And, out of them all, 20w50 vs 10w40 are the two most efficient multi-grade oils that can be used both in summers and winters as well. So, let’s check out their specifications in detail to choose one.

20w50 vs 10w40

The automobile industry uses a classification system, which is also known as the SAE grade. This grading system numbers these engine oils to elaborate upon their viscosity rating.

For the case of 20w50 and 10w40, the viscosity at low and operating temperatures vary. However, they have certain similarities and quite a lot of differences for you to consider.

Therefore, if you are willing to opt for one among these two, referring to this 20w50 vs 10w40 article is your best bet.

20w50 Specifications

20w50 is manufacturer-specified engine oil. It means that you should use it only when the manufacturer’s manual says so. It is mostly preferable for vehicles that have the efficiency of running at high temperatures.

Also, this oil is primarily suitable for summer cars. However, it is also an ideal pick for vehicles running in the winter season as well.

A Porsche car engine block with oil deposit

If you drive your vehicle at high speed for quite a long time, then the engine starts to heat up. And, the heat within the engine can cause serious wear and tear if enough lubrication doesn’t reach the components.

Apart from that, if you are living in a cold region, where the vehicle is idle in the garage for a week or more, it needs a cold start. And, with ideal lubrication of 20w50, you can efficiently get that cold pumping in the engine.

The reason why it is preferable for both summer and winter cars is its viscosity. The numbers within the oil type, 20w50, specify the viscosity at low and high temperatures.

The number 20 denotes, viscosity of the oil at low or winter temperatures. And, the number 50 denotes the viscosity of the oil at high or operating temperatures.

If the vehicle is a highway fleet or a pick-up truck, it usually runs more than the passenger cars. And this, in turn, demands a budgeted oil, as the need for replacement is often. Therefore, 20w50 is an ideal oil specified for heavy engines to give them proper lubrication and long life.

10w40 Specifications

10w40 is yet another popular engine oil in the lot and is preferable for modern-day vehicles or engines.

In addition, all the vehicles above the year 2012 come with modern engines that require more prominent lubrication and cold temperature pumping. For heavy-duty engines, 5w40 could be an alternative for 10w40. Therefore, 10w40 oil is considered an ideal pick for fast vehicles or usually runs in cold climates.

10w40 oil is expensive, as it is preferable for passenger cars or light vans, without the frequent necessity of changing the oil.

A close up shot of an oil deposit

In addition, 10w40 provides a better flow to the engine components and offers protection to the bearings and piston skirts when they generate heat.

However, getting the oil of the right viscosity is important to reduce friction, slow down the wearing process, and support easy starting.

The numbers on its name indicate the viscosity of 10w40. For example, the number 10 indicates the viscosity rating of this oil at low temperatures, whereas the number 40 indicates the oil’s viscosity rating at high or operating temperatures.

Furthermore, 10w40 is preferable for better start-up protection of the engine. 15w40 is also a good consideration for this relative to 10w40. Nevertheless, all the vehicles that come with high-performance engines, or are track vehicles, can prefer using 10w40.

Similarities of 20w50 and 10w40

  • Both these oils are ideal for both summer and winter temperatures.
  • They have good oxidation and thermal stability.
  • Cold starting is effective with the use of either of these oils.

Differences of 20w50 and 10w40

  • 10w40 offers better fuel economy than 20w50.
  • Also, 10w40 is quite better in terms of preferability in cold regions than 20w50.
  • 10w40 is an expensive oil in comparison to 20w50.
  • The low-temperature viscosity for 10w40 is 10, whereas for 20w50 oil, it is 20.
  • The high-temperature viscosity for 10w40 is 40, whereas for 20w50, it is 50.

Major Distinguishing Factor

The major distinguishing factors between 10w40 and 20w50 engine oils depend on their viscosity index. The viscosity index of 10w40 is 150, whereas it is 130 for 20w50 oil. The higher the viscosity index, the better is the oil output!

Fixing a car engine

When to Use 20w50?

I prefer to use 20w50, only if your vehicle manufacturer recommends you for the same. If not that, you can opt to use this oil for your heavy and old engines.

If the average running time of your vehicle is high, then you need an engine oil that is less expensive for frequent replacement. In addition to that, 20w50 is ideal for both summer and winter climates.

When to Use 10w40?

10w40 is a bit expensive engine oil, but it has good protection attributes in comparison to 20w50. Also, it is a better choice for vehicles operating in cold climates.

Moreover, if you have a modern vehicle with a high-performance engine that demands extreme protection and lubrication, 10w40 is an ideal pick.

Final Verdict

Every oil has its quality, and that is what makes it stand out from others. Therefore, check your manufacturer’s manual to see what oil types are ideal for your vehicle, such as synthetic oils or regular oils.

However, viscosity and temperature can be the deciding factors while choosing an oil for your vehicle. If 20w50 and 10w40 are compatible with your vehicle, consider these differences and similarities to decide the one among these two oils.