8 Best Oil For Duramax On The Market 2023:(Synthetic & High Mileage!)

If you’re looking for the best oil for Duramax, then you’ve stumbled on the right guide. Few diesel engines are dominant in the inner workings of the top diesel trucks like Duramax.

So you must use the best available oil on the market.


Best Oil For Duramax [Top 8 Picks]

Shell Rotella T[5 Gallon,5W-40, ]
Liqui Moly[5 Liter,5W-40]
Mobil 1
Shell Rotella T
Mobil 1
Royal Purple
Mobil 1

What is the best oil for Duramax?

If you use one of these high turbo engines,  knowing the right oil for Duramax is essential.

The most dependable oil for Duramax is the Rotella 550046217 Shell T6 Full Synthetic Heavy Duty Engine Oil.

Why is Rotella Shell T6 Full Synthetic Heavy Duty Engine Oil the best brand oil for Duramax

The Shell Rotella T6 hails supreme because of its advanced performance irrespective of temperature condition and its efficient engine protection from wear.

Top 8 Best Oil For Duramax Review

01. Rotella Shell T6 Full Synthetic Engine Oil  – Best dual-use


Highlighted Features

  • Protection from harmful contaminants
  • Protection from engine wear
  • Improved fuel economy
  • Highly compatible with the emissions system
  • Resistant to extreme heat
  • Good performance in low temperature
  • Exceptional shear strength

Product details and performance

The Shell Rotella T6 is compatible is multi-purpose and can serve a diesel truck just as well as a gasoline engine.

Thus, stocking up on this heavy-duty engine oil saves users with dual engine purposes from trying to identify the best oil for each.

It combines superior additive technology with a fully synthetic base to produce a formula that’s resistant to extreme weather.

In summer or winter, the viscosity of the engine oil can withstand extreme weather conditions, making it ideal for harsh operating conditions.

Its clean formula enhances performance and increases its ability to defend your engine from soot and dirt.

In addition to that, this heavy-duty engine oil offers total compatibility with virtually all engine emission systems.

Thanks to its low-ash nature, it gives an extra layer of protection to the vehicle’s structure from the toxic by-products generated by the engine’s after-treatment of the exhaust.

Compared to its predecessor, the API CJ-4 engine oil, it is much gentler on your engine parts and maintains their integrity and performance for much longer.

”The only problem worth noting about this otherwise exceptional oil is that it is hard to come across in the market and not always in stock.”

Product Specifications

  • Manufacturer: Rotella
  • Brand: Shell Rotella T
  • Weight: 5W-40
  • Manufacturer part number: 550046217


  • Dual-purpose for gasoline engine
  • Resistant to wear
  • Enhanced fuel efficiency
  • Temperature protection
  • Extended oil life
  • Pocket friendly
  • Increased viscosity


  • Hard to find

02. Liqui Moly Premium Synthetic Motor Oil: Best environmentally friendly


Highlighted Features

  • Fully synthetic
  • High-grade additives
  • Dual engine concepts use

Product details and performance

The German brand Liqui Moly produces Liqui Moly 2041 Premium 5W-40 Synthetic Motor Oil.

With over sixty years of experience manufacturing quality diesel oil, it’s no surprise that the Liqui Moly premium makes this list.

Most deserving of recognition is its unique formula made to maximize any engine’s efficiency and be gentle to the environment.

This high-grade motor oil is designed with the right additives to enhance its flow and instantly lubricate the engine’s inner surfaces.

Coating the interior surfaces of the engine’s system doesn’t take away from its oil saving capabilities.

Advanced technology slows down the rate at which it burns oil and extends this motor oil life.

”Although saving fuel saves money and sounds economically better, its initial cost is still on the upper side compared to other similar diesel oils.”

However, with a weight of 5W-40, its viscosity rating in colder climates also makes it easier than most to get started.

Its added convenience in cold starts and other beneficial attributes like fuel efficiency and increased lubrication justify its high demand.

Product Specifications

  • Manufacturer: Liqui Moly
  • Brand: Liqui Moly
  • Weight: 5W-40
  • Manufacturer part number: 2041


  • Efficient in extreme weather
  • Improved fuel economy
  • Environmentally friendly
  • Marked engine cleanliness


  • Higher price

03. Mobil Synthetic Motor Oil – Best for gas mileage


Highlighted Features

  • Improved engine cleanliness
  • Better mechanical support
  • Tolerant to extreme temperatures
  • Decreased oil burning

Product details and performance

This synthetic motor oil’s premium formula is beloved by high-performance European vehicle users for its unrivaled ability to extend gas mileage.

Not only is it recommended by Duramax engines, but top car manufacturers like Mercedes and AMG recommend this oil as well.

This synthetic oil doesn’t burn quickly, increasing intervals between an oil change, thereby adding more comfort for you.

Mobil 1 is highly suited to reduce the rate of oil burning, which consequently extends its life span.

More mileage on less oil automatically translates to less frequent trips to the auto-shop to stock up on more engine oil.

Harsh weather is no deterrent to this refined engine oil.

Its brilliant mixture is resistant to extreme operating temperatures, allowing you start-up your engines without trouble under the thickest blanket of snow.

Its unique weight measurement of 0W-40 means its viscosity rating ranges between 0 – 40, depending on the weather.

This versatile ability to change the texture to suit the weather’s needs makes it ideal for any climate condition.

”Before jumping to purchase this premium quality engine oil, it might be beneficial not to be on the more expensive side of the spectrum than other oils.”

The Mobil 1 OW-40 Synthetic Motor Oil has an excellent viscosity rating, allowing it to immediately lubricate the car’s engines’ inner workings and reduce friction.

This attribute, combined with its enhanced additive contents, guarantees the increased mechanical performance of your truck.

Product Specifications

  • Manufacturer: Mobil 1
  • Brand: Mobil 1
  • Weight: 0W-40
  • Manufacturer part number: 112786


  • Increased engine wear protection
  • Extensive gas mileage
  • High performance in extreme weather
  • Reduced engine deposit


  • More expensive

04. Shell Rotella T5 Synthetic Blend Diesel Engine Oil – Best for wear protection


Highlighted Features

  • Advanced technology against wear
  • Great control over engine deposits
  • Increased temperature tolerance
  • Increased resistance to oil breakdown

Product details and performance

From the renowned engine oil brand Rotella T5 comes the highly efficient Shell Rotella T5 Synthetic Blend 15W-40 Diesel Engine Oil.

Its unique standard formula design effortlessly works with your system’s engine.

The Rotella T5 is mostly exceptional when it comes to maintaining the truck’s inner parts’ integrity.

It sets itself apart from the market by not only beating but exceeding maximum wear requirements.

Moreso, it’s advanced synthetic blend technology incorporates the highest quality additives to ensure it is free-flowing even in cold weather.

Its viscosity is stable during harsh weather due to its superior supplement ingredients.

Manufactured using the best Triple Protection Plus technology offers highly effective mechanical performance throughout its long life span.

”However, if you plan to use the Shell Rotella T5 in an engine with geared motors, you might not get the best results.”

Still, this magnificent engine oil is one of the best oil for Duramax engine users because of its high-grade specifications that meet the mark for several other vehicle recommendations.

Due to its excellent formula, the Rotella T5 is slow to burn, which elongates its lifespan.

Its composition design interacts with the engine’s systems through improved oxidation reactions that reduce oil per mileage breakdown.

All that contributes significantly to its efficient and noteworthy control of exhaust deposits.

Product Specifications

  • Manufacturer: Rotella
  • Brand: Shell Rotella T
  • Model: T5
  • Weight: 15W-40


  • Maintains function in extreme weather
  • Increased engine wear protection
  • Improved durability against particles


  • Not suited to geared motors

05. Mobil Super Motor Oil – Best Budget


Highlighted Features

  • Extremely versatile
  • High mechanical performance
  • Fully backward compatible
  • Meets gasoline engine requirements

Product details and performance

The Mobil Super 15W-40 Delvac 1300 Motor Oil offers the best of both worlds in terms of price and performance.

Its highly efficient formula conserves oil for longer, without compromising on its commercial output.

If you have an older diesel engine truck, and you’re worried about how modern technology would perform with old and delicate systems, then worry no more.

Through rigorous compatibility tests, Mobil ensures this engine oil can function in all previous engine series, making it one of Duramax’s most fitting oils.

Adding to its perks is the density that allows it flawlessly to adapt and retain optimal functionality in the cold.

A weight of 15W-40 is proof of its vast-ranging ability from a viscosity of 15 in colder temperatures to 40 under normal operating conditions.

As a result, it is perfectly capable of delivering high-out results when the temperature drops.

The Mobil Super 15W-40 Delvac is an excellent heavy-duty oil even for commercial purposes.

Its high-performance quality reduces emissions output and deals with particles from the after treatment with ease.

If you have a mixed fleet in your garage, it might be beneficial to know the Mobil Delvac is highly versatile.

It is conventional oil that is useful in diesel engines and meets the requirements for gasoline engines.

Product Specifications

  • Manufacturer: Mobil 1
  • Brand: Mobil 1
  • Weight: 15W -40
  • Manufacturer part number: 96819


  • Economically friendly
  • Lower oil consumption
  • Offers great versatility


  • Turns black easily

06. Royal Purple Oil 15W40: Best Lubricant


Highlighted Features

  • Advanced additive technology
  • Superior engine compatibility
  • Optimized engine performance

Product details and performance

The unique combination of an excellent base with advanced additive supplements sets the Royal Purple 15W-40 apart from the rest.

It delivers outstanding engine performance in a diesel truck and gasoline vehicles, making it a double function option for the average user with a mixed fleet.

There’s more to the high-grade additives than dualizing this oil’s capabilities.

It also ensures high-quality engine performance with enhanced control over exhaust deposits.

”The only setback of this otherwise magnificent product is that the packaging is not always accurate. At times it doesn’t come with the right amount of fluid, and you might be a few ounces short of a gallon.”

But no matter the amount, you can expect premium protection for your engine parts against agents of degradation like soot and other defects.

Plus, through the high-grade technology involved in its processing, this high-performance motor soil seamlessly adapts to all engines.

You can upgrade in a flash as there are no requirements or unique treatments necessary before making a switch.

Product Specifications

  • Manufacturer: Royal Purple
  • Brand: Royal Purple
  • Weight: 15W -40


  • Improved mechanical performance
  • Good lubricant
  • Effective contaminant deterrent
  • Seamless fuel upgrade


  • May have an inaccurate amount

07. Mobil Delvac 1300 Super Motor Oil: Best For Quiet Engine


Highlighted Features

  • Optimized thermal and oxidation stability
  • Extended TBN reserves
  • Excellent shear stability
  • Better Fuel economy
  • Long oil life
  • Extreme temperature tolerance

Product details and performance

Mobil 112786 15W-40 Delvac 1300 Super Motor Oil is a high-grade diesel oil with the right formula to keep your Duramax’s engine in top quality.

Its excellent shear stability prevents corrosive by-products from doing severe damage to the engine’s system.

It is highly resistant to wear and maintains the integrity of your vehicle’s structure for more extended periods.

”On the downside, it is only available in quart containers, meaning you have to be extra careful when pouring it into the oil filter so it doesn’t spill.”

Otherwise, the Mobil Delvac 1300 Super is very efficient when it comes to oil conservation.

Its superior technology makes it spectacular at maximizing quantity without sacrificing its high output.

Its viscosity rating is also very flexible and can adapt with ease to winter’s harsh weather conditions.

Better temperature tolerance means it’s not likely to let sludge build-up and block the channels within your engine.

Its unique additive blend even meets API requirements for gasoline engines, so it’s ideal for mixed fleets.

Product Specifications

  • Manufacturer: Mobil 1
  • Brand: Mobil 1
  • Weight: 15W -40
  • Manufacturer part number: 112786


  • Improved engine efficiency
  • Resistant to sludge build-up
  • Protection against corrosion
  • Excellent temperature tolerance


  • Only available in quart containers

08. Amsoil Signature Series Synthetic Motor Oil: Best For Old Engines


Highlighted Features

  • Preserves Horsepower
  • Reduced oil consumption
  • Better temperature performance
  • Oil breakdown resistant

Product details and performance

Last but certainly not least, in terms of performance, Amsoil Signature Series 5W-30 is as good as any oil for Duramax.

It uses the latest motor oil manufacturing technology, making it an ideal product for turbocharged direct injection.

The Amsoil Signature series, through its design, keeps engines healthier by preserving valuable horsepower.

Engine output is maximized throughout a trip like never before, thanks to its ability to retain torque.

The Amsoil Signature Synthetic oil does that without wasting oil unnecessarily.

It falls well below the volatility limit, ensuring this motor doesn’t evaporate too quickly and lasts much longer.

”Its life expectancy reduces when it mixes with other oils or additives. Hence, upgrading to this motor oil brand may require special treatment to get the most out of it.”

There’s no cause to add additives to it anyway. Its supplements are high-quality technology tested to provide impressive temperature tolerance.

Unwavering in the top percentile of motor oils for colder climates makes starting trucks in sub-zero weather a walk in the park.

Product Specifications

  • Manufacturer: Mobil 1
  • Brand: Mobil 1
  • Weight: 15W -40
  • Manufacturer part number: 112786


  • Engine wear protection
  • Greater fuel economy
  • Increase engine durability
  • Convenient cold-starts
  • Improved engine cleanliness


  • Short life expectancy

How To Buy The Best Oil For Duramax

Now more than ever, we have more options for choosing the best oil for Duramax.

Most oils have the same components on the surface, but they differ widely when you get into the specifics.

Oil engineers emphasize determining what supplements to add because it affects how well the oil handles extreme temperatures and how compatible it is with specific engines.

Hence, you must go through a checklist of attributes good oil should have before making a purchase.

Here are the top buying considerations to keep in mind when choosing diesel oil.

Fuel economy

Without a doubt, engines are more expensive than the oil they consume, so you must select the best one.

Still, diesel oil can be quite expensive, and having to purchase another gallon at regular intervals can be frustrating.

You can maximize fuel economy through different methods.

Some diesel oil reduces the time interval needed between oil drains, which is also less stressful for you.

Others may have more sensitive fuel triggers.

Fuel economic diesel oil might be slightly more expensive than one that’s not, but going for the oil with better fuel economy extends your mileage and saves more money in the long run.

Engine compatibility

Many oils meet the manufacturer’s standard requirements, but for Duramax trucks with more power, you might want to consider upgrading your oil.

It’s uncommon to find street truck engines make more power than full out race truck engines at the drag strip.

Now standard street truck engines aren’t built to be fast, but they can be between 700 – 100 horsepower.

So you need an oil that can withstand that kind of power and still do a lot of mileage.

Moreso, you need to factor in the kind of engine you have. Older trucks sometimes require a different type of oil.

It’s essential to keep this in mind when purchasing a used truck because the engine is not brand new.

Never forget to cross-check the weight of the oil. The design of a  lot of Duramax engines caters to 15W 40, but it still differs.

Some modern engines require lighter oils of around 5W 40 or 5W30. So use the weight specified for your truck.


The viscosity of an oil is its resistance to flow. It is how hard it is to push fluid through a hole.

The resistance of flow is significant because it keeps oil between the bearing in, the rod, and the crank.

When the engine oil pressure starts, the oil pump sucks it up from the tank and pushes it through a hole that opens into a channel where it lubricates the engine block and rod bearings.

So it pressurizes the piston, the crank, and other parts of the system.

If the viscosity rating is not right, the oil will be unable to flow correctly and lubricate the car’s system’s vital interests.

Viscosity is also affected by temperature. If it’s too cold, it’ll affect the viscosity rating and make it too hard to move.

Most formulas are multi-grade so that they can function effectively without much disruption from the weather.

Still, certain oils work better than others under certain conditions.

Take, for example, the 5W-40 isn’t as attuned as the 15W-40 for colder temperatures.

Temperature protection

The most significant factor that affects viscosity is temperature.

Seeing as there’s not much you can do in altering the weather, getting an engine oil that offers temperature protection is a close second.

If the weather is too cold and the viscosity is too high, high-powered engines will be a problem as the oil will quickly gel together and not lubricate the system well enough.

Higher temperatures will result in deposits in the engine system, which can hinder the engine’s life span.

Getting oil that has an added layer of temperature control can save you a great deal of trouble.

Look out for effective oil under varying weather conditions, primarily if you reside in a place that experiences a broad spectrum of temperatures across the year.

Oil type

There are two primary grades of diesel oil, conventional and synthetic oil. Most manufacturers will recommend synthetic oil for Duramax.

But some people will make a blend of both, and that’s perfectly fine.

However, what you put in the oils can determine many things like viscosity and whether it’s good enough to support your engine on long distances.

In the diesel industry, oils are continually changing, and it has more to do with the additives than the base oil itself.

The latter is usually static and hardly changes. Supplements vary according to the standards set and periodically revised by the API (American Petroleum Institute).

Specifications change because manufacturers are continually upgrading the emissions systems to produce less soot and toxic substances.

So no matter what type of oil you opt for, it’s crucial to ensure it meets API specifications.

Additive package

There is an infinite number of debates on conventional diesel vs. synthetic oil.

While each has its unique properties that make them appealing, the additive package of the oil you eventually decide on is more important.

Why? The base oil makes about 10%, while the other 90% is what people put in the oil, which accounts for more than the oil type.

Companies using preserve their best additive packages for their premium oil because they realize how essential the supplements are.

The best additive packages have the added advantage of being more resistant to wear because they’re good lubricators.

The lubrication also assists the efficiency of the engine’s interior parts as it protects them from corrosion.

For colder climates, additives help preserve diesel oil’s texture and prevent it from gelling together.

That’s why synthetic oils tend to be more expensive than regular oils because they contain extra injected additives.

People Also Ask About Best Oil For Duramax

How often should I change the oil in my Duramax?

Old oil has a higher tendency to gel and cause an engine knock because of all the particles it has accumulated over time.

Under standard operating conditions, you should change your engine oil every ten thousand miles (eight thousand kilometers).

In severe operating conditions, you’ll have to change the oil more often, perhaps for half the mileage as under normal conditions.

If you’re not sure how to gauge distance accurately, then to be safe, change the oil about every six months.

Dusty areas will need a more frequent oil change.

Also, pay attention to the car’s warning signals, and change the oil when indicated on the dashboard.

How do I change the fuel filter of a 6.6 liter Duramax?

Locate the fuel filter. It’s usually right below the prime bottom and above the car’s sensor.

It’s easier to access by taking out the inner fender wall, as you can’t see the fuel filter in a Duramax from the top of the engine.

Before starting, disconnect the water and fuel sensor. Once that’s out of the way, you can use an oil wrench to dispose of the old diesel fuel.

Next, read the instructions for the new filter before installing it.

The filter head has two o-rings around it, take both of them off and lubricate them before putting it back on the filter head.

Go ahead and screw the filter head on to the body of the new filter.

You can use a 13-millimeter screwdriver to tighten the bleeder screw after using an oil wrench to put in the new fuel filter.

If done correctly, it should take about 20 -25 minutes to complete.

Why does diesel oil turn black so fast?

Diesel oil is not very appealing to look at or get on your hands or clothes when it’s black.

So why is it different from gasoline oil, which doesn’t turn dark as quickly?

First of all, there’s no cause to worry if your diesel oil turns black after a few days; that’s normal.

The reason diesel differs from gasoline in this respect is the added soot.

Gasoline engines produce less soot because they mix with air before entering the combustion chamber, but diesel enters at the combustion point.

Thus, the lack of air or at least reduced air causes the latter’s fuel to turn dark faster.

So when your engine is not up to full operating temperature, or the air filter is plugged or even hot-rodded.

How do I store my diesel oil properly?

Poorly stored diesel fuel can cause your engine to knock, creating unnecessary complications for you, so it’s crucial to learn how to store it properly.

Cold-weather isn’t very friendly with diesel fuel, so investing in anti-gelling supplements can come in handy during winter.

Many auto-part stores keep them in stock, and they’re not very expensive.

A single can of anti-gelling supplements can preserve as much as twenty to thirty gallons of diesel fuel.

These additives prevent the oil from gelling together when the temperature drops.

Without it, most trucks would have a problem starting in sub-zero weather.

As a rule, always store diesel fuel in a clean place.

The area should also be dry because when water meets oil there is a hydrolysis effect that negatively affects the quality.

In addition to that, when water comes in contact with metal, such as the tank used to store diesel fuel, it causes rustication.

Rust can also affect the oil’s integrity. So keep the tank cool and away from water that can also encourage microbial growth.

How long can I store diesel oil?

Yes, even diesel oil expires eventually. When properly preserved, Duramax’s diesel oil has an average life expectancy of anywhere between six to twelve months.

However, through proper storage, you can extend the life span of your oil.

First, you have to preserve it carefully. Keep it away from threats that can alter its quality, such as water, microbes, and extreme temperatures.

How do I replace the diesel filter head on a Duramax engine?

The fuel filter head on your Duramax engine serves many purposes.

It mounts the fuel filter, acts as the primer for the fuel system’s supply side, and houses the fuel heater to aid in cold weather operation.

To replace the diesel filter head, start by removing the former filter head and then removing the plastic bleeder screw and the primer pump assembly.

Hold the rubber boot with a red wire and give it a slight twist while pulling it off the heater.

Finally, remove the other two screws carefully remove the plunger assembly by lifting it straight off.

After removing the metal cap, turn the filter head upside down and remove the two screws holding the head-on.

Clean the filter housing so no contamination is present.

Then carefully rebuild the layout with a new filter head.

Don’t forget to clean the new lip seals with a few brake cleaner shots before attaching it back to the plastic primer housing.

Ensure the first seal points towards the phalange, and the second is pointing away from the phalange.

How do I bleed air out of my fuel on a Duramax?

Air can contaminate even the best oil for Duramax, and if not left alone, can have adverse effects on your engine.

There are different ways of bleeding out the air from your fuel, depending on your truck’s configuration.

The easiest way is with an engine that has a lift pump.

After priming the lift pump, turn on the truck for about twenty seconds and crank it.

What happens is the pump will send fuel up to the injection pump and get rid of the air.

Alternatively, pumping on the primer ball when the bleeder screw is loose will allow air purge out of the system.

Once the air escaping sound stops, screw the bleeder back on carefully, making sure not to make it too tight.

Also, keep your face and fingers clear of the Schrader valve, as that’s the air’s escape route.


There’s a popular comparison between cars and the human body. Suppose engines are like the heart.

Then, Duramax diesel engines are like an Olympic athlete’s heart.

Just the way you watch what goes into your heart, pay attention to what oil goes into your Duramax engine.

Now that you know the best oil for Duramax, carefully determine which specifications meet your most needs, and weigh them against their draw-backs.

georgelawsongallery.com is a participant of the Amazon Affiliate program. We may earn a small commission if you purchase through our recommended links. More details.

Leave a Comment