Sae 30 vs 15w40: What’re The Differences?

Choosing the right engine oil for your automotive vehicle is a very crucial step that is important for low maintenance cost and long life for engine components.

Earlier we’ve discussed the difference between Sae30 and 5w30 engine oils. This was an in-depth analysis of these two most popular engine oil categories, you can check out it.

Today I’m going to clear every doubt regarding SAE30 Vs.15w40 engine oil.

What are the differences and which one is best for which temperature ranges?

Let’s find out…

But wait…

If you are in hurry then this brief comparison table will definitely save your time to understand these two terms at a glance.

Sae30 Vs 15w40: Similarities And Differences

Sae30 Engine Oil15w40 Engine Oil
1. Sae30 is a hot viscosity grade oil.15w40 is a cold viscosity grade engine oil.
2. Sae30 is only suitable for hot weather conditions in the operating temperature of 100°C.15W40 is suitable for varying temperature conditions. The word “w” here, indicates winter.
3. Sae30 is a monograde oil. 15w40 is a multigrade oil.
4. It is best to use in some old cars, bikes, lawnmowers, and generator engines.It is best for modern and heavy vehicles such as trucks, loading-unloading vehicles, SUVs, etc.
5. Sae30 doesn’t have detergents.15w40 comes with several useful additives with detergent.
6. Not good to clean dust, debris from the moving parts of the engine.It can clean dust and debris from the engine components.
7. You can not use Sae30 where 15w40 is recommended.You can use 15w40 in place of Sae30.
8. It is either synthetic or mineral oil.It is also available in mineral and synthetic variants.
9. Economic lubricant for old vehicles.A little bit more expensive than Sae30.

15W40 Vs. SAE30: Which One Is Better?

Let me first clear some very basic but important terms so that you can understand them well without getting confused.

What Is SAE30?

SAE (Society Of Automotive Engineers) is an international organization for individual Engineers and its headquarter is in Warrendale, Pennsylvania. It provides different grades to the automobile products such as engine oil, etc, and defines which automobile product is best for use in which conditions.

sae30 engine oil (View On Amazon)

The engine oil viscosity rating is defined between 0 to 60, according to the SAE J300 standard. Low-graded oil seems thinner than high-graded oil. Sae viscosity grade defines engine crankcase and gear oil only.

SAE30 is a monograde oil, also referred to as a single-grade oil. The word SAE30 contains one number, in our case, it is 30, which means its viscosity rating is 30.

A single grade oil can be rated either as a warm viscosity grade or a cold viscosity grade. In our case sae30 is a hot viscosity grade oil.

Sae30 Is A Hot Viscosity Oil, What Does It Mean?

The term viscosity for oil is a very important parameter to judge whether a particular oil is good or not for your machine.

SAE30 is a hot viscosity oil. Viscosity refers to how fast or slows an oil can flow through all the machine components at the operating temperature.

Where I Can Use SAE30 Engine Oil?

SAE30 can be used in small engines mostly in your lawnmower, snow blower, small tractor, etc. As sae30 is a non-detergent oil, you can use it in air compressors and hydraulic systems where there is no need for detergent oil.

Some 4 stock gasoline engines as you can see in motorcycles, powerboats, and in some 10 to 20 years old cars, SAE30 based engine oil is fine.

What Is 15w40?

Unlike Sae30, 15w40 is multigrade engine oil. Where Sae30 is a hot viscosity grade engine oil, 15w40 performs best in varying temperature conditions. Multigrade oils are made of a combination of base mineral oil and some special types of additives. Additives are mixed up in the multigrade oils to boost up their performances for various conditions.

15w40 engine oil (View On Amazon)

There are some benefits of using a multigrade engine oil instead of a monograde oil…

  • Provide betten engine cleanliness.
  • It disperses very well to the whole area.
  • It protects engine parts from corrosion and from severe wear or tears.
  • It has better thermal-oxidative resistivity.

Sae 15w40 or 15w40 has two parts in its name. The first part 15w describes the flowability of this engine oil at cold temperature. The engine oil can be used up to -25° Celsius beyond this limit its flowability is lost because it gets thick.

Here, the suffix “W” stands for winter.

The second part 40 indicates that the engine oil is flowable at the operating temperature of 100° celsius.

The Sae 15w40 is functional within the following temperature range

Low-Temperature LimitHigh-Temperature Limit
-25° Celcius100° Celcius

Where Can I Use 15w40 Engine Oil?

As early stated 15w40 is a multigrade oil and can perform better in varying temperature conditions than a monograde oil. It performs best within the temperature range of -25­­° Celcius to 100° Celcius.

Under What Circumstances Is 15w40 Not Usable?

15w40 engine oil is certified to use within the defined temperature range. In harsh winter conditions, it might not be thin enough to disperse in the engine.

Must check the compatibility of your automotive vehicle with 15w40 that is specified by the respective manufacturer.

What Is The Difference Between Sae30 And 15w40 Diesel Oil?

Many people have a very common doubt…

Is The sae30 and 15w40 Same?

If you read the above-mentioned detail carefully then the answer is very clear. No, they are not the same. Sae30 is a type of oil having a high-temperature viscosity grade.

While 15w40 has two grades, the viscosity grade 15 is for low temperature, and the viscosity grade 30 is for when the engine is operated at high temperature. The engine oil with grade 15w40 can be pumped down to -25° C in the engine.

15w40 is an ideal choice for different temperature conditions due to its multigrade properties. It can provide better protection to your engine parts in varying temperature conditions.

When the temperature goes down in winter, 15w40 helps to crank the engine in such a cold condition and perform better than sae30.

On the other hand, Sae30 performs best and can protect the engine from wear and tear in only hot temperatures (100°C).

Can I Use 15w40 Instead Of Sae30?

The answer is yes, although the oil types have different viscosity grades, it is better to use a multigrade engine oil instead of a single grade engine oil.

It also depends on which engine type your machine has. if it is a lawnmower, motorcycle, or others. In old machines like lawnmowers, generators, old bikes, etc using Sae30 is fine.

SAE30 Vs. 15w40: Detergent Property

Detergent additives are mixed up in the engine oil to protect engine components from dust and debris. Engine oil with added detergent additives can trap and dissolve the impurities in the oil, and the cleaning process is continued till the oil changes.

SAE 15W40 comes with detergent additives which provide 25% better protection against impurities than a non-detergent engine oil like SAE30.

15w40 Is Mineral Or Synthetic Oil?

15w40 is manufactured in both varieties. Many brands offer two different types of oil in the category of 15w40. You can either choose their conventional engine oil based on mineral oil or can choose their fully synthetic oils.

The difference is in their pricing. A mineral-based 15w40 will cost you much cheaper than its Synthetic varient. Here, you can see the price advantage in its mineral varient but mineral-based oil has one major disadvantage. Its performance is very poor and unstable in varying temperature conditions than synthetic-based oil.

Can I Mix 15w40 With SAE30?

Every engine is designed to perform in its optimum capability with compatible resources. Engine oil does the same job. Different engines require different oil types having some specific viscosity grade rating.

You are not allowed to mix 15w40 with sae30 because both engine oil has different viscosity grading. 15w40 is a multi-grade oil, on the other hand, sae30 is a monograde oil.

Although mixing the same grade engine oils such as sae30 and sae40 is acceptable mixing two different grade oils is not advisable.

Can I Use 15w40 Oil In My Bike?

It totally depends on what type of bike you own and what does its manufacturer recommends using as its engine oil. It also depends on the age of your bike. If your bike is old and has covered more than 50k km then 15w40 would be fine but use a higher grade oil in old vehicles because there are chances of oil leakage. Thicker oil works great in this situation.

Can I Use 15w40 In My Lawnmower?

A lawnmower is mostly used in summer which means an engine oil with hot viscosity grade is perfect for a lawnmower.

15w40 might be not suitable to use in such a tiny engine. In Lawnmowers like tiny machines oil level is more important than its viscosity.

You can choose sae30 or 10w30 for your lawnmower. A lawnmower engine requires such oil that can lubricate its whole area without getting thick at high temperatures.

Can I Use 15w40 As Hydraulic Oil?

15w40 is a multigrade oil with high viscosity, on the other hand, hydraulic oil has low viscous properties. If you pour a high viscous oil in place of low viscous oil then it’s perfectly fine.

This is very common to use a multigrade oil like 15w40 in the construction and agriculture machinery in place of hydraulic oil.

15w40 is a combination of mineral or synthetic oil + several friction additives. 15w40 contains detergents that absorb moisture from the fluid in the molecular form and do not create bubbles.

Multigrade oils are the best cleansing agent, and their capability of bearing high temperatures without changing the viscous property makes them best for all purposes.

Is SAE30 Thicker Than 15w40?

Sae30 is definitely a thicker engine oil than its counterpart 15w40 in cold temperature conditions. 15w40 remains thin in the cold weather and disperse well in the engine while Sae30 remains thick and doesn’t disperse well.

On the other hand, Sae30 perform well in high temperature and is limited to use in some old 2-stroke and 4-stroke diesel engines, whereas 15w40 can be used in hardworking cars, trucks, and SUVs.


Choose the perfect engine oil for your expensive vehicles wisely because you are going to use your vehicle for a long period of time.

Without the proper engine, oil or a bad cheap oil will lead to a high maintenance cost and severe wear and tear to your vehicle engine parts.

Sae30 is best for only high-temperature conditions and is only suitable to use in some 2-stroke, 2-stroke engines in oil devices and vehicles.

Whereas 15w40 is useful for varying temperature conditions and can be used for heavy vehicles such as trucks, buses, SUVs, loading and unloading vehicles.

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