Best Oil for Diesel Engines Reviews: You Should Know

Cars can be the bane of our life or the answer to our prayers. That is why car owners go the extra mile when it comes to maintenance to extend the lifespan of their vehicle. Regular servicing and maintenance are a chore, but it is necessary for the preservation of your vehicle.

One of the things that you need to invest on is engine oil. Engine oil for your diesel engine helps the engines run smoothly. Diesel engine oil should not be confused with diesel fuel.

Diesel oil contains more additives because diesel engines are subjected to harsher conditions. Diesel oil also absorbs more carbon than gasoline oil.


Shopping for the Best Diesel Engine Oil

Choosing the best oil for diesel engines is crucial. Vehicles don’t have the same requirements when it comes to diesel oil. If you notice that your engine is not performing as it used to and you notice darker emissions, it could be time for an oil change. Ask your mechanic if you need to change your diesel engine oil as well.

Keep in mind that you should only use the recommended diesel oil as provided in your manual. Expensive products do not mean they are better. Here are some tips on how to choose the best oil for your diesel engine:

Check the viscosity grade

best oil for diesel engines

Viscosity is the thickness or stickiness of the oil. You can find the viscosity requirements on your vehicle’s manual or the oil container label. The number before the “W” represents the viscosity (“W” stands for “winter”). The lower the number, the better it works in cold weather.

Check the labels

best oil for diesel engines

Look for the starburst symbol beside the donut-shaped symbol on your engine. The starburst symbol tells you if you have a diesel or gas engine and if your engine has been tested. The donut-shaped symbol tells you what oil your vehicle requires.

This symbol also shows you the current service level rating, where “C” stands for diesel engines. So, what does it mean when the donut symbol shows 5W-30? This means that the required oil should have a viscosity of “5” (recommended for colder climate) and functions best until the temperature reaches 30 degrees.

Think of the climate in your area

best oil for diesel engines

If you live in a region where there are abrupt changes in temperature, this affects the performance of your diesel oil. If the oil is too thick or viscosity is too high, it may take longer to warm and run through your engines.

Oil thickens as it cools and thins as it warms. If you live in a region where there are sharp changes in temperature, you may consider adding additives to your oil. Additives help oil resist too much thinning.

Think of how old your vehicle is

best oil for diesel engines

Older vehicles mean more sludge. Single-weight oils don’t have detergent in them so they can’t clean your engines well. You may need to switch to multi-viscosity oils to free up the grime in your engine, so it functions better. As your engine gets older, it may be harder for the oil to reach into those small spaces.

Consider your vehicle’s mileage and usage

best oil for diesel engines

If your vehicle is overused and travels long distances, choose a heavy duty oil specifically for your engine. The oil should be thin enough to travel smoothly through the smallest gaps in your engine.

However, the oil should also be thick enough, so it doesn’t burn too quickly. Older engines exhaust more effort, so it burns oil quicker.

Different Types of Diesel Engine Oil

To better help you evaluate which is the best oil for your diesel engine, here are the various types of diesel oil:·

  • Full Synthetic Oil
  • Synthetic Blend Oil
  • Premium Conventional Oil 
  • Higher Mileage Oil 

This is the most expensive oil which is typically used on high-tech engines such as Chevrolet and Mercedes-Benz. What’s great about fully synthetic oil is that they last longer and pass very stringent tests. The oil is thin enough to flow freely at low temperatures and lubricates well even at high temperatures.·

Top 5 Diesel Engine Oils

We looked around the market and reviewed the different diesel engine oil products. Here are our recommendations to help you choose the best oil for your diesel engine:

This fully synthetic motor oil has one for both diesel and gasoline engines. It is compatible with both synthetic and conventional motor oils. It is also compatible with fuels containing ethanol. Royal Purple Motor Oil contributes to fuel efficient and offers better protection against engine wear.


  • Noticeable change in engine performance even for older trucks.
  • Dropped the engine temperature even when carrying heavy loads.
  • Oil pressure is still good even when idling.


  • It came up ¾ short of 20 quarts, not enough for 2 oil changes for a diesel truck.

Shell fully synthetic diesel engine oil provides better protection and helps maintain cleanliness of your engines. It is excellent even with extremely high or low temperatures. Its oil measures at SAE 5W-40. It has low ash additive in a synthetic base oil that adapts to your driving conditions.


  • Best for cold temperatures.
  • Affordable


  • Some customers reported that it lost its lubricating factor after some time

This heavy duty diesel engine oil provides triple action that helps clean deposits and emissions, control engine wear, and adapts to engine protection needs. It weighs 15w-40 and meets API-CJ4 requirements.

It also provides a 30% decrease in ash which protects against sludge and deposits. It gives all-around protection for turbo and non-turbo engines.


  • Affordable
  • Convenient to buy


  • Not recommended for motorcycles

This high mileage motor oil weighs SAE 20w-50 which means it has high viscosity. It has superior detergent that helps clean older and high mileage engines. The seal conditioners help reduce leaks making it more efficient.

The advanced additives help prevent your engine from wearing out quickly. It also exceeds ILSAC GF-5 and API SN standards.


  • Burns less
  • Noticeable difference in older engines


  • More expensive than other brands

This synthetic oil provides excellent cleaning power for older engines that have accumulated sludge. Since it measures 0W-40, it is excellent for low temperatures for rapid engine protection. It also helps you save on fuel consumption. Since it has low viscosity, it delivers fast engine protection even in hard-to-reach gaps.


  • Affordable
  • Cheaper than most brands
  • Recommended for most diesel engines
  • Can be used on older vehicles


  • Not BMW approved


Now that we have explored the different types of diesel engine oil and the various products in the market, we have come up with the best diesel engine oil based on price, quality, and efficiency.

For this round, we chose Mobil 1 120760 Synthetic Motor Oil 0W-40, 5 Quart because it is the most affordable and comes in 5-quart containers.

Another reason why we chose this is that it is highly recommended for colder temperatures and provides excellent lubrication up to 40 degrees Fahrenheit. Meaning to say, it fully adapts to your engine’s conditions as well as the normal climate.

best oil for diesel engines

Oil filling.

Since this oil is fully synthetic, it has just the right amount of additives and detergent that cleans your car as it lubricates it. We also checked the reviews, and we found no negative reviews about it damaging engines. It truly works as it is advertised.

The only downside is that it is not recommended for BMW cars. But then again, there are not too many BMW car owners out there ( I had no idea that BMW has diesel engine vehicles).

When choosing the best oil for diesel engines, make sure that you always consult your vehicle's manual before using another kind of oil that was recommended by your dealer. 

best oil for diesel engines

Make sure that you regularly bring your car for servicing and change the oil and filter at the recommended time.

Also, make sure that you regularly bring your car for servicing and change the oil and filter at the recommended time. Even if you use the best diesel engine oil, but you don’t take it to the automotive shop for maintenance, your engine still suffers.

What do you think of the products above? If you have recommendations or have tried out other products not on the list, feel free to give your suggestions. You may also send your feedback and comments to us. Please share this article with fellow car enthusiasts and other vehicle experts.

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