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Best motor oil 10w-40

Choosing 10w-40 oil for your car? In this article, we will tell you what to look for when choosing 10w-40 viscosity oil.

10w-40 oil is typically used for high mileage vehicles, over 70 miles for hot climate use.

To make the right choice when choosing an engine oil for a car, it is not enough to be aware only of brands, viscosity, and temperature modes of products, you must, first of all, take into account the tolerances of the car manufacturers. The wrong choice of lubricant can cause serious engine problems, leading to an unwanted overhaul.

In this article, we will explain how to make the right choice and not face a number of troubles. Let’s consider all the advantages and disadvantages of 10w-40 oil, technical characteristics, tolerances from car manufacturers, as well as at what mileage the car should consider this product.

How is 10w-40 deciphered?

The most important indicator of engine oil is its SAE viscosity, which serves as an international standard. The temperature range, within which the oil does not lose its qualities, places it in one of the classes.

Lubricant marked 10w-40 has the following deciphering:

The designation 10w shows the temperature range in winter operation, the second part of the abbreviation “40” indicates the maximum ambient temperature in hot climates.

10w-40 Motor Oil Best Choice

Best choice

Mobil 1 High Mileage Full Synthetic Motor Oil 10W-40

Mobil 1 High Mileage contains a seal conditioner to help reduce oil leaks in higher mileage vehicles, and its uniform synthetic oil molecules reduce friction, helping to prevent deposits and sludge buildup.

  • 4,9 Rating
  • API SP, SN Plus, SN, SM
  • ACEA A3/B3

Best 10w-40 motor oils on the market:


Valvoline High Mileage with MaxLife Technology SAE 10W-40 Synthetic Blend Motor Oil

Valvoline High Mileage with MaxLife Technology SAE 10W-40 Synthetic Blend Motor Oil


  • Rating: 4,8 ∗∗∗∗∗
  • API: SP, SN, SN Plus.
  • ILSAC: GF-6A.


Castrol GTX High Mileage 10W-40 Synthetic Blend Motor Oil

Castrol GTX High Mileage 10W-40 Synthetic Blend Motor Oil


  • Rating: 4,8 ∗∗∗∗∗
  • API: SP, SN, SN+, SM.
  • ILSAC GF-5.


Liqui Moly Anti-Friction 10W-40 Motor Oil

Liqui Moly Anti-Friction 10W-40 Motor Oil


  • Rating: 4,8 ∗∗∗∗∗
  • ACEA: B3, B4.
  • API: SL/CF.


Havoline 10W-40 Motor Oil

Havoline 10W-40 Motor Oil


  • Rating: 4,7 ∗∗∗∗∗
  • API: SP.
  • Protection against thermal breakdown.


Quaker State Conventional 10W-40 Motor Oil

Quaker State Conventional 10W-40 Motor Oil


  • Rating: 4,7 ∗∗∗∗∗
  • API: SN (and all previous categories).
  • Combats engine sludge and deposits.

Characteristics of SAE 10w-40 oil

10w-40 oil is viscous enough to leave a thick, dense film of oil on engine parts. In terms of protection when starting in summer it will show itself better than low viscosity oils: in one or two days of idling the car, the liquid oil completely drains into the sump. The first second of a start-up in this case is always accompanied by dry friction. Viscous oil, on the other hand, leaves a thin protective film that protects the engine from starting wear.

SAE 10w-40 oils are produced mainly on a semi-synthetic basis because the high viscosity allows the use of cheaper base oils. Exceptions are oils for heavy-duty trucks, which need synthetic lubricants due to long service intervals.

Some manufacturers make specialized SAE 10w-40 synthetic oils for sports or harsh conditions.

Let’s highlight the main characteristics of 10w-40 automotive oil:

  • 10w-40 oil is versatile in climatic use, for light frosts and hot enough heat;
  • 10w-40 oil is only suitable for engines with higher mileage, as synthetic oils can burn out faster;
  • 10w-40 oil is cheaper and can protect the engine in the most unacceptable conditions. 10w-40 oil is also suitable for engines that run at high speeds;
  • When you use 10w-40 viscosity motor oil in your car, it’s well-suited for your car’s best start with minimal;
  • At any given time of day and temperature, it will give your car the best possible start.

What the automakers’ recommendations are based on

Recommendations for the use of engine oil are based on the peculiarities of the engine design. For example, it is the size of the clearances in the friction pairs: the larger they are, the thicker the oil film that separates the metal parts must be. After all, in a running engine, there is no metal-to-metal contact; all the parts are separated by the thinnest layer of oil. Newer engines, which have a more precise friction pair fit and use metals with a low thermal expansion coefficient, require less viscous oils.

If the recommendation specifies oils with viscosity 0w-40, 5w-40, 10w-30, 10w-40, then you have to choose from these variants. If you pour more viscous oil, you can not only lose power and fuel consumption (more viscosity – more friction force in fluid layers) but also lead the engine to overhaul. In addition, oil channels can be so thin that too viscous oil will not pass through them even when it is not too cold. Conversely, for engines that require viscous oils, an oil film that is too thin will result in vibration and dry friction.

You can often find recommendations to use higher viscosity oils if the engine has already gone 70,000 miles. It makes sense: no matter how carefully the owner took care of his/her car, mechanical parts are slowly wearing out. The clearances in the engine become a little bit bigger, and it means they need a little bit thicker oil film. But even in this case, the choice of a more viscous oil should be made from the list of allowable degrees of SAE. And, of course, be guided by the technical condition of the engine.

Types of motor oils

The composition of modern motor oils is formed on the principle of adding a specific set of additives to their base (sometimes called base oil).

The base oil can be derived from:

  1. From artificially synthesized organic compounds – in this case, oils are called synthetic.
  2. A mixture of mineral and synthetic bases – semi-synthetic oils.

Fully synthetic engine oil 10w-40

Fully synthetic 10w-40 oil provides higher viscosity, resistance to oxidation and thermal degradation, and helps fight oil sludge. It helps improve fuel efficiency and can even increase vehicle power by reducing engine drag.

Fully synthetic oil is ideal for vehicles that require maximum performance and high levels of lubrication. If you live in a climate with very cold winters or very hot summers, or if you use your vehicle for towing or hauling cargo, synthetic oil may be the best type of oil for your vehicle. Older engines can also benefit from synthetic oil because it can help prevent the harmful sludge that some older engines are prone to.

Since the cost of synthetic motor oil is higher than regular oil, consult with your technician to see if this oil is right for your car.

10w-40 Synthetic Blended Motor Oil

Synthetic 10w-40 oil has many of the characteristics of fully synthetic oil, but at a lower cost. This type of oil consists of a blend of synthetic and conventional base oils with the addition of some additives that provide additional resistance to oxidation and excellent low-temperature properties. Synthetic blends make it easy for drivers to switch from conventional oil to synthetic oil, so this type of oil is becoming increasingly popular among today’s drivers. It’s also a great intermediate option for drivers who want the added protection and performance of synthetic oil but aren’t willing to pay for a full switch to synthetic oil.

Conventional 10w-40 Engine Oil

This oil is great for low-mileage, low- to medium-mileage late-model cars with a simple engine design.

10w-40 engine oil for higher mileage engines

The 10w-40 high mileage oil is specifically designed for vehicles with over 75,000 miles. This type of oil helps reduce oil consumption, minimize oil leaks and seepage, and reduce smoke and emissions in older engines.

SAE and API classification 10w-40

Car oils are classified according to two key indicators: the scope of use: gasoline/diesel engine, turbocharged engine; oil viscosity.

The standards by which lubricants are classified are considered the same for all oils. The most common is the SAE and API classifications.

The API standard introduces two groups of quality classes, prefixed with S (gasoline engines) and C (diesel).

The letter after the prefix defines a particular class, assigned to new classes in order of alphabetical order: API SP oil meets more stringent requirements than API SL.

If a particular oil grade can be used in engines for both types of properties, a double class is specified – for example, API SN / CF.

API classification divides oils into three groups according to their purpose and quality:

  • S – for gasoline engines;
  • C – for diesel engines;
  • EC – universal energy-saving oil.

The other letters indicate the class the grease belongs to. All classes differ from each other:

  • API SL – oils for engines in cars manufactured after 2000. For multi-valve, turbocharged, with work on lean mixtures, with increased requirements for energy efficiency and environmental friendliness.
  • API SM – oils for engines of cars manufactured after 2004. Ability to be certified according to ILSAC energy-saving category.
  • API SN – oils for engines of vehicles manufactured after 2010. Designed for oils used in the most advanced gasoline engines of passenger and sports cars and small vans. Some oils in this category may comply with the ILSAC GF-5 specification and qualify as energy-saving.
  • API SP – oils for engines of cars manufactured after 2020. Designed for oils used in the most advanced gasoline engines of passenger and sport utility vehicles and small vans. Some oils in this category may meet ILSAC GF-6 specifications.

ILSAC 10w-40 engine oil classification

  • GF-4 – oils for engines of vehicles manufactured after 2004, SAE viscosity grades 0W-20, 5W-20, 0W-30, 5W-30 and 10W-30. The oils are compatible with catalytic exhaust gas recovery systems.
  • GF-5 – oils for engines of vehicles manufactured after 2010 meet the quality requirements of API SN classification. Viscosity grades SAE 0W-20, 5W-20, 0W-30, 5W-30. They are characterized by improved energy efficiency, enhanced anti-wear properties, provides reduced sludge formation in the turbine, a noticeable reduction of carbon deposits in the engine.
  • GF-6 – oils for engines of cars manufactured after 2020, includes improvements: fuel economy and preservation of fuel economy, preservation of engine life, protection from wear.

Recommended oil brands 10w-40:

  • Liqui Moly.
  • Mobil.
  • Castrol.
  • Havoline.
  • Quaker State.
  • Shell.
  • Valvoline.
  • Pennzoil.
  • Lucas Oil.
  • Amsoil.

The cost of 10w-40 engine oil:

  • Up to $20: synthetic-based 10w-40 oils.
  • Up to $25: 10w-40 synthetic oils from popular brands.
  • Up to $50: 10w-40 synthetic oils from premium brands.


To select the right type of multigrade 10w-40 engine oil, the car owner must take into account the engine type of his car, the manufacturer’s recommendations on the use of technological fluids produced by the partner company.

In the absence of such recommendations, it is necessary to be guided by the mileage and condition of the engine of your car, as well as your own financial capabilities. But it is best to use 10w-40 engine oil based on semi-synthetic on cars with mileage, in conditions of year-round operation. It is the semi-synthetic type that has the best price-quality ratio.

Max Welder (rvneeded)

Max Welder (rvneeded)

Max Welder is a mechanic enthusiast. Currently, working at a small company. Experienced in electronics, car tools, and security systems. In his spare time, he writes articles for various blogs.

One Comment

  • jeddah says:

    The products are blended out of virgin base oils from Lube-Ref, ARAMCO, which is well known for highest quality of crude oils and manufacturers of high volatility and low sulfur bases oils in the whole world. The blending plants are situated both in Saudi Arabia and UAE. Our manufacturing involves highest standards of raw materials, additives and base stock. The products are tested and approved by the major international OEMs 10w40 engine oil.

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