Best Oil for Duramax Diesel Engines

Last Updated:
Best Oil for Duramax Diesel Engines

Best Oil for Duramax Diesel Engines

Best Oil for Duramax Diesel EnginesBest Oil for Duramax Diesel Engines

The Duramax diesel engine is a powerful V8 engine for trucks characterized by a high level of horsepower and torque. An engine like this needs good quality oil for proper lubrication. Buying the best oil for Duramax diesel engines is, however, not a small undertaking. This article will present some of the best oil solutions you can use in Duramax engines. This should make it less overwhelming for you to make the right choice of oil for your engine.

Comparison Table of 5 Best Oil for Duramax Diesel Engines

1. Mobil Super 96819 Motor Oil

Key Features

  • Excellent Thermal Stability
  • 15W-40 Viscosity
  • Good Shear Stability

Mobil makes some of the best motor engine oils and this Mobil Super Delvac 1300 Motor Oils one of their best products for Duramax diesel engines. One of the exciting highlights of this oil is its extended oil drain interval that makes it a superior formulation compared to most oils in the same category. The oil is also characterized by impressive shear stability that can prevent the damaging effects of corrosive by-products.

Like you would expect from any oil recommended for Duramax, it is highly resistant to wear. While the oil is not synthetic, it has the advantage of being more versatile and suitable for various engines. Additionally, the Mobil Super 96819 has a viscosity of 15W-40, which is quite thick, by the way. This makes it extremely resistant to wear in hot temperatures.


  • It meets API requirements
  • It versatile for use in different engine types
  • It improves fuel efficiency


  • Cold start performance not so impressive

2. Shell Rotella T6 Full Synthetic Diesel Engine Oil

Key Features

  • Fully Synthetic
  • Improved Heat Resistance
  • Impressive System Compatibility

One of the things you can expect from this Shell Rotella Diesel Engine Oil is improved fuel economy, thanks to Shell’s unique low ash formulation technology. It is especially suitable for heavy-duty diesel engines like Duramax. The formulation contains multi-functional dispersant additives that protect the engine from the negative actions of soot and deposits. With a viscosity of 5W-40, it performs well in extreme operating temperatures and provides optimal protection during long service intervals.

Furthermore, the oil can resist viscosity loss and maintain the right pressure in the engine. Another exciting thing about Shell oil is that it is compatible with emission control systems. The excellent wear and corrosion protective effect it has considerably improved the lifespan of engines. The improved API CJ-4 synthetic formula gives it a much more protective effect than older generation oils. Given its potent lubricating effect on heavy-duty engines, it is a highly recommended oil for Duramax engines.


  • It can be used with exhaust emissions control systems
  • It has positive effects on vehicle emission compliance
  • Improved heat resistance


  • Not always available on the market

3. Royal Purple ROY04154 Oil

Key Features

  • Proprietary Additive Technologies
  • Extended Engine Compatibility
  • Improved Additive Technology

Pure synthetic oils like the Royal Purple 04154 15-W40 Oil have always been recommended for Duramax engines by automotive professionals. More than that, this oil contains robust detergents and the right set of additives for deposit removal and engine cleanliness. The 15-W40 viscosity grade is perfect for a cold start and high-temperature performance. By its ability to trigger fast segregation of deposits, it is able to protect against engine wear. Moreover, the formulation is compatible with mineral or other synthetic oils.

As it exceeds the performance standard of ILSAC and Dexos 1 specifications, you can be sure that your engine will not be starved of lubrication. One interesting thing to note is the extended engine compatibility. This means that it can be used in both older and recent engine models in addition to its compatibility with synthetic and mineral oils. At high and low temperatures, the oil can maintain its protective effects, but its performance could be slightly compromised at very low temperatures.


  • It is fully compatible with other oils
  • It contains additives that protect against corrosion
  • Prevents the accumulation of deposits


  • Not the best for cold starts 

4. Liqui Moly 2041 Premium Synthetic Motor Oil

Key Features

  • Fully Synthetic Oil
  • Multi-Functional Additives
  • Excellent Fuel Economy

Our next recommendation for many searching for the best diesel oil for Duramax engines is the Liqui Moly 2041 Premium 5W-40 Synthetic Motor Oil. The fully synthetic oil formulation is just what you need to lubricate and prevent deposit build-up in a heavy-duty engine. In addition, with its viscosity rating of 5W-40, it can resist thickening in very cold conditions for superior engine performance. Likewise, it does perform excellently at higher temperatures.

Interestingly, the Liqui Moly 2041 is compatible with contemporary engine concepts like turbocharging, multi-valve arrangement, and more. As a result of its positive effect on smooth engine running, it ensures fuel efficiency and reduces the emission of pollutants. Like many Duramax engine oils, it contains multi-functional additives that enhance its flow and instant engine lubrication. Also, the lubricative effect is so durable that it persists even in extended oil change intervals.


  • Enhanced flow for instant lubrication
  • Perfect for a cold start
  • It prevents engine corrosion and wears


  • It is quite costly

5. Valvoline Premium Diesel Engine Oil

Key Features

  • One Solution Technology
  • Conventional Motor Oil
  • Outstanding Oxidation

The Valvoline Premium Blue SAE Oil features a special One Solution Technology that gives it a very wide range of applications that includes diesel and natural gas heavy-duty engines. It is also formulated for high performance in emissions treatment engines, including those that feature contemporary diesel technology like diesel particulate filters and exhaust gas recirculation. The Valvoline oil has a 15W-40 viscosity rating which means it is highly functional at moderate and high temperatures and decent enough at cold temperatures.

Furthermore, the oil is characterized by outstanding oxidation resistance for long oil life in heavy-duty engines. Although it is a conventional motor oil, it offers sufficient protection against oxidation and corrosion, ensuring that the engine is kept cleaner for a longer lifespan. The lubricative and protective effect on Duramax engines also makes for better fuel efficiency. For people. The Valvoline Premium Blue SAE 15W-40 Diesel Engine Oil is what we recommend for those searching for the best oil for 6.6 Duramax diesel engines.


  • Versatile for use in a wide range of heavy-duty engines
  • Good performance at high temperatures
  • Better fuel efficiency


  • Not the best oil for a cold start

How To Choose the Best Oil for Duramax Diesel Engines?

Choosing the best oil for Duramax diesel engines is not so different from buying engine oil for other motor engines. But, most importantly, you should make sure that your oil choice is compatible with your Duramax engine for the best lubricative and protective effect under different temperature conditions. Here are some of the features and factors to consider:

Oil Type

With regular and synthetic oil types to choose from, you could get quite confused about choosing the right oil type for your engine. Many automotive professionals recommend synthetic options for Duramax engines. Nonetheless, a good quality conventional oil can likewise perform well in a Duramax engine. Whatever option you go for, the important thing is to choose a product that is compatible with your Duramax engine.


Viscosity is one of the most important things to check when choosing oil for any engine. With heavy-duty engines like Duramax engines, it becomes even more important. Viscosity is a measure of oil’s resistance to flow. Without the right level of Viscosity, the oil cannot flow properly and lubricate the essential parts of the engine. This oil flow characteristic is considerably affected by temperature, so it’s important to consider your climate also. 


Multi-functional additives characterize modern motor engine oils. Some offer improved wear protection, while some work to ensure better fuel efficiency. Choosing the right additive package will considerably improve your engine functionality, but too many additives can reduce the functionality of the base oil. 

How Much is Duramax Oil Capacity?

The oil capacity of Duramax engines vary slightly across different engines, but generally, a Duramax engine can take about 10 quarts of motor engine oil with the oil filter and around 9.5 quarts without a filter.

Is Synthetic Oil Better for Diesel Engines?

Synthetic oil is considerably better than regular oil for diesel engines. For one, synthetic oil has a better flow rate at cold temperatures, making it possible for important engine parts to be lubricated on startup.  On the other hand, it retains Viscosity at higher temperatures to provide constant lubrication to the engines.

Synthetic oil is generally more expensive than conventional motor oil, but it also has the advantage of lasting much longer than conventional oil. The excellent deposit prevention also means that it helps to maintain much cleaner diesel engines. Another advantage of synthetic oil over conventional oil in a diesel engine is the extended oil change interval. 

How to Change Duramax Oil?

Changing the oil in a Duramax engine is quite similar to changing the oil in any other motor vehicle. With the right tools and supplies, you can go through the process yourself. Nevertheless, it is always a good idea to let a qualified automotive professional handle the oil changing.

1. The first thing to do is place a suitable drain pan under the engine oil pan to collect the oil as it drains.

2. Next, undo the drain plug from the oil pan with a socket or a box-end wrench, and allow the oil to drain out.

3. Replace and tighten the drain plug, but do not overtighten it

4. Unscrew the oil filter from its mount and get the replacement filter ready

5. Lubricate the new oil filter gasket with new motor oil and install the oil filter by hand. Tighten as tight as you can

6. Through the oil fill tube on top of the engine compartment, pour in the new engine oil and check the oil level with the engine oil dipstick

7. After filling in the oil, start the engine and leave it running for about five minutes.

8. Check the oil level again and check for leaks around the oil pan and filter casing. 

How Do I Change the Fuel Filter of a 6.6 Liter Duramax?

Here’s a step by step guide to changing the fuel filter of a 6.6 liter Duramax engine

  • To access the fuel filter, reach through the wheel well at the front passenger side, remove the small plastic clips that connect the plastic guard to the rear of the wheel well.
  • With the fuel filter now visible, locate and disconnect the electrical connector of the water-in-fuel sensor.
  • Move to the engine and rotate the fuel filter anti-clockwise to remove it, but be sure to keep it upright as you remove it to prevent the fuel from spilling. Drain the fuel afterwards.
  • Remove the water-in-fuel sensor with pliers and change the o-ring inside with the new one that comes with the fuel filter.
  • Lubricate the water-in-fuel sensor o-ring with engine oil and fix it on the new fuel filter.
  • Install the replacement fuel filter. Find and open the bleed valve to the driver side of the fuel priming pump
  • Pump the plunger on the fuel filter housing continuously until fuel starts to flow out of the bleed screw opening. Close the bleed screw immediately. Fix and replace all other loose elements and start the engine.

Frequently Asked Questions (FAQs)

1. What’s the Duramax oil change cost?

There are two major costs you might incur when changing Duramax engine oil. The first is the cost of buying the replacement oil, which could be anything from $20 to $80, depending on the type of oil you’re going for. The other cost is the professional service cost if you’re not able to change the oil yourself and have to get a professional to do it.

2. Why does diesel oil turn black so fast?

It is only normal that diesel oil turns black faster than gasoline because diesel engines produce much more soot. Diesel doesn’t mix with air before entering the combustion chamber, and this lack of air causes it to turn black much quicker.

3. What’s the Duramax oil change interval?

The manufacturer’s instruction concerning oil change interval should be followed carefully at all times. However, for most Duramax engines, the recommended oil change interval is usually between 5000 – 7000 miles, 


High-quality oil is very important in maintaining the overall functionality of an engine. If your vehicle has a Duramax diesel engine, these oils we have reviewed are some of the best to ensure satisfactory engine performance. To make your whole oil changing process less stressful, we have also discussed some important things to know about Duramax oil changing, as well as factors to consider when picking out oil for your engine.

Leave a Comment