6.0 Powerstroke 5w40 Vs 15w40 oil – (Detailed Comparison)

The choice between 5w40 engine oil and 15w40 depends on the winter temperature of the area and the manufacturer’s recommendations.

5w40 synthetic engine oils, for instance, perform better in colder places because of their low viscosity while cold. The 15w40, on the other hand, are mineral oils that do better on heavy-duty engines. They both work better in protecting your 6.0 Powerstroke engine when it’s fully operational by reducing its wear and tear effect.

Engine oil’s role in the engine is to lubricate the engine parts constantly under friction. By reducing friction, the amount of wear decreases significantly, and the engine temperature is regulated. The oil viscosity, which is the oil’s resistance to flow, should be equitable for your engine.

6.0 Powerstroke 5w40 vs 15w40 comparison is based on several factors ranging from the environment condition to temperature.

6.0 Powerstroke 5w40 Vs 15w40

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6.0 Powerstroke 5w40 Vs 15w40 – key Differences

There are several aspects to consider when comparing these two options. In the following chart, I have written several comparisons of the 5w40 and 15w40 oil engines on the 6.0 Powerstroke engine.

ViscosityThe 5w40 has a lower viscosity of 5 measured at 104°F15w40 has a higher viscosity level of index 143
Temperature range-22°F to 122°F-15°F to 122°F
Engine typePetrol and Diesel engines can use itDiesel engines
Price1 quart $30 at Amazon1 quart $67 at Amazon
DetergentsPhosphorousPhosphorous, zinc

What Are the Engine Oil Numbers And Their Meanings?

The numbers on the oil label indicate the viscosity as tested by the Society of Automotive Engineers. The letter “W “stands for winter, and the number before specifies the oil’s behavior while cold. The number after the letter indicates the oil viscosity after the engine runs and in high temperatures.

Below are common engine oils for 6.0L Powerstroke engines.

  1. 0W-30 – The engine oils with 0W-30 oil grade have zero winter flow-ability at 0°F. They are not affected by the cold and have 30 densities at running temperatures.
  2. 5W-30 – 5W-30 grade engine oils have a viscosity of 5 at 0°F and 30 at warmer temperatures. They are ideal for 6.0L Powerstroke engines operating in both warm and cold areas.
  3. 5W-40 – 5W-40 grade engine oils have the same viscosity as 5W-30 at cold temperatures, but have a higher viscosity of 40 at 210°F.
  4. 10W-30 – 10W-30 grade engine oils have a 10 viscosity at 0°F and 30 at 210°F. These oil grades are ideal for warmer places and heavy diesel engines, including 6.0 Powerstroke engines.
  5. 15W-40 – 5W-40 grade engine oils have a 15 viscosity at 0°F, which might be too thick to start in cold areas. The 40-grade density is however ideal for both warm and cold places

5w40 Vs 15w40 – (detailed)

There are several factors to consider while comparing both 5w40 and 15w40 graded engine oils on a 6.0L Powerstroke engine. Follow closely as I take you through right below.

A Brief Description On 6.0 Powerstroke Engines

6.0 Powerstroke engines are powerful diesel engines manufactured between 2003 to 2007 by Ford. The engine has a Navistar-built turbo-diesel and 560 lb-ft at 2000 rpm torque, ideal for heavy-duty engines.

A Brief Note On 5w40

5w40 graded engine oils are synthetic oils with a viscosity of 5 at cold temperatures. This low density is ideal for cold areas, and the 40 viscosities also work better for heavy-duty engines.

A Short Note On 15w40

15w40 graded engine oils are denser with the 15 viscosity enabling these oils to have a stable temperature during use. The 15w40 grade oil viscosity has a superior soot dispersancy and anti-oxidation than other grades.

5w40 Vs 15w40: Is One Better Than the Other?

One of the factors that stands out when it comes to the differences between these two oils is viscosity. The higher density of the 15w40 makes it recommendable for heavy-duty engines and maintains the high viscosity better than the 5w40. The 5w40 lower viscosity makes this oil better for colder areas of about negative 22°F.

The 5w40 engine oils are extensively used all year round because they adapt better to weather conditions. The usage range of 5 to 40 compared to the 15 – 40 serves as an advantage to users using the 5w40 oils. However, for a heavy-duty operation, the 5w40 oils are often too thin to operate at maximum potential.

5w-40 synthetic & 15w-40 Dino

If you’re wondering which choice between 5w-40 synthetic and 15w-40 Dino is better, below are the key details.

Synthetic oils like the 5w-40 are created from chemically modified materials. They contain fewer impurities than organic dino oils and work exceptionally with high-performance engines. Unlike synthetic oils, where the manufacturing starts from scratch, dino oils are created by filtering unrefined oil products. The final product is the 15w-40 dino oils, which are quality oils and recommended for heavy-duty engines.

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Which Is the Ideal Oil For 6.0 Powerstroke?

The prime factors to consider when choosing the engine oil for your 6.0 Powerstroke engines are manufacturer recommendations and winter conditions. For cold places, I would recommend the 5w40 oils which have a lower viscosity making them the best oil for 6.0 Powerstroke in winter. However, if the location is warm and the truck is for heavy-duty use, go with the much thicker 15w40.

How Often Should I Change Oil In My 6.0 Powerstroke?

Most vehicles have 5000 miles oil change rule, especially the heavy-duty engines using the 15w40 oil. However, some vehicle engines can run for up to 7500 miles on synthetic oils like the 5w40.

Vehicle usage sometimes determines the frequency of the oil change regardless of the viscosity of the oil used.

What Happens When You Use the Wrong Engine Oil?

Oils can either be too thick to lubricate when cold or too thin when the engine is fully performing. If you’re in low-temperature areas, the engine will have issues running if you wrongly use thicker oil.

I suggest you visit your manufacturer to change your engine oil to the recommended grade.

Frequently Asked Questions (FAQs)

The engine oil differences have been an ongoing debate for decades. While each oil has some advantages over the other, many questions arise. I have carefully compiled the commonly asked questions and their comprehensive answers.

Can I Use 5w40 Instead Of 15w40?

The choice of the engine oil to use will be determined by the area temperatures where the engine is running. However, in most cases switching from the 15w40 to 5w40 synthetic oil will result in faster startups and lower fuel use. Still, I recommend the engine manufacturers do the engine oil change.

Can You Mix The 5w40 And The 15w40?

The safest thing to do is use each separately and drain one type before using the other. However, mixing the synthetic 5w40 with the 15w40 oils is okay, with no significant problems encountered from this act. Combining the two oils will result in oil of about 10w40, which might be thicker for starting in colder places.

5w-40 vs 15w-40 >> Check out the video below:

The Takeaway

The debate on the 6.0 Powerstroke 5w40 vs 15w40 engine oils can be settled by observing several factors. The vital determiner is the oil’s viscosity, where the 5w40 thinness works better for cold places. The 15w40 tends to maintain the performance during a heavy-duty run than the 5w40.

Despite the 6.0L Powerstroke engine having several problems in its early days, if well maintained, it performs tremendously. With suitable engine oil and regular maintenance, this powerful engine can leave to its promise.

With the knowledge from this article, you can now decide on the fuel to use more comfortably.

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Mahir Ahmed


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