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10w40 AGL

What is 10w40?

The Society of Automotive Engineers (SAE) standard for motor oil specifies a weight of 10W-40, which refers to the oil’s viscosity.

The viscosity of 10W-40 oil is 10W at cold and 40 at hot temperatures.

Cold motor oil is thicker than hot oil. The viscosity of 10W-40 engine oil does not increase with temperature and vice versa. It acts as a 10W oil at room temperature and a 40W oil when heated.

Power Rating Of 10W:

The oil has a cold viscosity of 10W.

At low temperatures, oils reach their maximum specified viscosity. The thinner the oil, the lower the viscosity ( “W” stands for Winter). The 10W oil thickness will be more appropriate during the colder months than the 5W oil.

The Prestigious 40:

When heated, the oil has a viscosity of 40.

This test measures oil flow at an operating temperature of 100 degrees Celsius in the engine. Seal leakage and the oil’s capacity to protect engine components at higher temperatures are the primary concerns of the hot viscosity rating.

At normal engine temperatures, a 40-weight oil will be much thicker than a 30-weight oil.

Why Do You Need 10W-40 oil?

Why Do You Need 10W-40 oil

A 10W-40 oil recommendation is not something you’ll see on a contemporary passenger vehicle.

However, it is still widely used in light vehicles equipped with medium- and heavy-duty gasoline engines. Diesel engines, as well as smaller motorbike engines, often utilize oil of this weight.

Also, older engines prone to burning or oil leaks might benefit from the 10W-40 oil viscosity.

When the temperature rises, the 10W-40 oil’s viscosity increases, making it a better choice. This makes it less prone to leak while still effectively lubricating the moving components of older, high-mileage engines.

Because of its increased resistance to thermal breakdown, the higher oil viscosity is also a great choice for high-temperature engines.

If you choose 10W-40 oil, a synthetic version can provide better protection during winter. When the temperature rises, mineral oil thickens up enough to protect the skirts of the pistons and the bearings, while synthetic motor oil flows more smoothly.

Instructions for Selection of Motor Oil


This may seem like an essential review when it comes to selecting motor oil, but some of your customers are well aware of what they are purchasing or using.

To be forthright about it, if a bottle of oil doesn’t include the following information, DON’T BUY IT; instead, keep looking until you find one that does.

  • Its intended use (motor oil, gear oil, automatic transmission fluid, etc.).
  • Engine oils come in a variety of viscosities, such as 10w-40, 5w-30, etc., whereas gear oils range from 80w-90 to 75w-90 and beyond.
  • Its conformance to applicable standards (including any applicable API or ACEA ratings)
  • Its Original Equipment Manufacturer (OEM) Approvals and their respective codes (MB229.5, VW504.00, FORD 913A, BMW LL04, etc.)
  • Ignore the marketing copy labels since they can be incorrect.

Reasons Why Should Be Careful


There is a rule of thumb that you can only use the oil according to the automotive type. For instance, you wouldn’t use A/T oil or gear oil in your internal combustion engine. Understanding the oil’s intended use is crucial.


Today, “Multigrades” (i.e., 10w-40, etc.) comprise the vast majority of commercially available oils.

Previously, multigrades were created so that people wouldn’t have to resort to the archaic practice of switching between thinner oil for winter and heavier oil for summer.

The 10w part of 10w-40, for instance, only implies that the oil must meet a particular maximum viscosity/flow at low temperature

When it comes to cold temperatures, oils with a lower “W” are preferred. That 5w is preferable to 10w, etc.

The “40” in “10w-40” indicates that the oil must have a certain viscosity at 100 degrees Celsius. This is a hard cap; any oils with a 40 in their name must meet it.

Again, a lower number indicates a thinner oil; at 100 degrees Celsius, a 30 oil is more fluid than a 40 oil. Whether a 30, 40, 50, etc., is necessary is detailed in your manual.

Buy Motor Oil For Your Automobile Based On Its Grade And Viscosity


The performance of an oil and the specifications that it has passed can be determined from testing, which also reveals the oil’s formulation.

All good oils should have both API (American Petroleum Institute) and ACEA (Association des Constructeurs Européens d’Automobiles) requirements; knowing what these terms represent is essential while perusing oil bottles.

Identify our engine oils and fluids to use in vehicles and other parts that are designed to work with your automobiles.

  • 10W40 is more suitable for motors/engines in winter
  • This specification often has both gasoline (S) and diesel (C) requirements.
  • Automobile engine oils with API-SL are suggested.