3 Best 10w-40 engine oil

As your car ages, it becomes more important to use the right motor oil. Not only does the right oil help keep your engine clean and running smoothly, but it can also help improve gas mileage.

10w-40 engine oil is multi-viscosity oil that is suitable for cars that have been running over 75K miles or more. This oil is made for using widely different temperatures that can range from as cold as -30°C/-22°F to extremely hot, which can go up to 40°C/104°F. 

So, what is the best 10w 40 engine oil, and how do you pick one suitable for your vehicle and weather? This guide will help you understand what makes 10W-40 ideal for your car and things to look at when picking one.

1. Pennzoil High Mileage Conventional 10W-40 Motor Oil

Pennzoil High Mileage Conventional 10W-40 Motor Oil is an excellent 10W-40 conventional oil, though many people mistake it for synthetic oil. 

This Pennzoil 10W-40 is an API-approved Motor Oil specifically designed for engines with over 75,000 miles. So it can help improve engine performance and significantly protect against wear and tear. It also provides excellent protection even for vehicles running over 200K miles. 

So if you have a vehicle that is a bit exhausted but still running, you should get this excellent 10w 40 engine oil to lubricate and protect your engine. This oil contains seal agent additives to prevent deposits and sludge build-up. 

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

Older cars can significantly benefit from Mobil 1 High Mileage Full Synthetic Motor Oil 10W-40, designed to help protect engines with over 75,000 miles.

This Mobil 1 10W-40 oil contains special additives to help protect against LSPI(low-speed pre-ignition). Low-speed pre-ignition can occur when oil films break down at high temperatures, shearing the oil in the process and can lead to engine damage. But Mobil 1 10W-40 oil is designed to protect your engine from that due to its compliance with ILSAC GF-6 standards. 

It also contains special additives to help protect against timing chain wear as timing chains wear out with age, leading to noise and decreased performance. But Mobil 1 10W-40 doesn’t let that happen to your vehicle.

Not only that, it’s backed by a 10,000-mile/1-year warranty.

2. Castrol 03094 GTX 10W-40 Motor Oil

Castrol GTX 10W-40 is an ILSAC GF-5 and API-approved conventional oil. But it also contains special additives that help it to perform better than other conventional 10w 40 oils. Castrol GTX 10W-40 is also designed to protect against engine wear in extremely high and extremely low-temperature conditions.

Castrol GTX is an excellent 10W-40 oil for those looking for the best 10w 40 engine oil within budget. It has a high “flash point, ” meaning it won’t “burn off” as easily in high temperatures. This makes it ideal for use in hot weather or for engines frequently subjected to high temperatures.

Castrol GTX also has a unique “clean-up” additive that helps to remove deposits and TriShield technology to prevent any build-up from your engine, keeping it running at peak efficiency.

3. Valvoline High Mileage with MaxLife Technology SAE 10W-40

Valvoline High Mileage with MaxLife Technology SAE 10W-40 is a great motor oil for high-mileage vehicles. 

As engines age, they can start to burn oil, leak oil, and develop other issues. The MaxLife Technology in this 10w 40 engine oil is designed to help address these problems and help extend engine life. It is a unique combination of premium synthetic base oils and additives formulated to help maximize engine performance and extend engine life in vehicles over 75,000 miles.

Overall, Valvoline SAE 10W-40 oil meets or exceeds the requirements of most major automakers for engines that require a 10W-40 motor oil. Most importantly, the price per quart of this 10w 40 engine oil is significantly less for the performance it provides.

What Does 10w-40 Mean?

10w 40 oil has a high viscosity index, meaning it will flow easily in cold weather and maintain its thickness in hot weather. 

 Well, the “W” designation in the 10W-40 stands for “winter,” and the “10W” means that this oil can flow at ten weight at temperatures as low as -25 degrees Celsius. 

The lower the number before the “W,” the better the oil will flow in cold weather. As the viscosity grade starts from 0W, 10W can be considered an oil that will moderate to high flow in cold weather. 

Lastly, The “40” in 10W-40 motor oil refers to the oil’s viscosity at a higher temperature, such as 100 Degree Celsius. So in higher temperatures, 10W-40 motor oil will weigh 40W. 

How to pick the best 10w 40 engine oil?

When it comes to choosing the right oil for your engine, there are a few things you need to take into consideration. Here is a detailed look at the factor you need to consider when picking the best 10w 40 engine oil

Weight of the oil

The first thing you need to consider is the weight of the oil. The 10w40 oil is a bit heavier than some other oils on the market, but it is still light enough to provide good protection for your engine.


The 10w40 oil has a slightly higher viscosity than some other oils on the market, but it is necessary if you live in too cold weather. This oil’s high viscosity and flow make it effortless to start your engine in icy weather.

ACEA, SAE, and API compliance 

API, SAE, and ACEA oil standards are critical to the proper function of modern engines. These standards help ensure engine oil meets the necessary specifications for viscosity, flash point, and other vital properties. 

The American Petroleum Institute (API) sets the minimum standards for engine oils used in automotive applications. The Society of Automotive Engineers (SAE) develops suggested practices and test methods for engine oils. The European Automobile Manufacturers Association (ACEA) also has engine oil specifications. 

API, SAE, and ACEA specifications help ensure that engine oils provide adequate protection against wear and tear while maintaining proper viscosity and other important properties. As a result, engine oils that meet these standards will help prolong your engine’s life and keep running smoothly.


The last thing you need to consider is the additives in the oil. The 10w40 oil has a higher concentration of additives than some other oils on the market, but it is still within the acceptable range and provides excellent protection against wear and tears..


Why is 10W-40 oil used in older vehicles?

10w 40 oil is designed for use in both new and older cars. But this oil is used more in older engines because thicker oils like 10W-40 are better for older engines that have run over 50K miles. As an engine ages, it tends to develop leaks. The thicker oil can seal the engine better, preventing leaks and maintaining the engine’s oil pressure. In addition, 10w 40 engine oil does a better job of lubricating the engine and keeps the engine clean by preventing deposit build-up and corrosion.

Is 10W40 oil good for summer?

It’s no secret that motor oil gets thicker in cold weather and thinner when it’s hot out. So, you might be wondering, is 10W40 oil good for summer?

The answer is yes! 10W40 oil is designed to maintain its viscosity in hot and cold weather, making it an excellent option for summer driving. One of the main benefits of 10W40 oil is that it maintains its viscosity in high temperatures. So, it won’t thin out when it’s hot out, which can lead to engine damage.

How long does 10w40 oil last?

Most car experts recommend changing your oil every 10,000 to 15,000 km or so, but that number can vary depending on your car, your driving habits, and the type of oil you use. If you use conventional oil, you can probably go a little longer between changes, but if you use synthetic oil, you might need to change it more often.

How long 10w40 oil will last depends on how often and hard you drive. If you do a lot of stop-and-go driving or drive in extreme conditions, your oil will break down faster and must be changed more often. In general, though, 10w40 oil should last for 8000 Km or so.

Can I use 10w-40 instead of 10w-30?

Yes, you can, but here is the catch: 10w-40 oil is thicker than 10w-30 oil, so it may provide better protection in hot weather or when your engine is under heavy loads. However, this thicker oil can also make your engine work harder, decreasing fuel efficiency.

The main difference between 10w-40 and 10w-30 oils is their viscosity. Viscosity is a measure of a fluid’s resistance to flow. 10w-30 oil has a lower viscosity than 10w-40 oil, which flows more easily. This can be beneficial in cold weather, as the oil will flow more readily and reach all the parts of your engine that need to be lubricated.

Final words

Overall, the 10w40 oil is a good choice for your engine. However, it is a bit heavier than other oil on the market. Still, it’s excellent for handling the extra heat and stress and protecting your engine regardless of the weather you live in. but if you ask me to pick one of the best 10w 40 engine oil, I will go with either the Castrol or the Castrol GTX 10W-40 Motor Oil or the Valvoline SAE 10W-40 for the combination of the price and performance these two provide. 


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