diesel , diesel engine oil , duramax , duramax oil change , engine oil

Should I Analyze My Duramax Engine Oil?

Should I Analyze My Duramax Engine Oil?

At Merchant Automotive, we love implementing modern technology to solve problems for our customers.

One of the oldest conundrums in automotive maintenance is the question of oil change intervals. “Change your engine oil every 3,000 miles” used to be the common guideline that was championed by our dads and well, our dad’s … dads. Let’s just say this mentality has been around for a really, really long time and that it doesn’t really keep you as the customer in mind. For most modern vehicles, including Duramax-equipped trucks, synthetic oil makes the “change it every 3,000” guideline incredibly wasteful and costly. In fact, most synthetic engine oil-equipped vehicles can easily be pushed to over 10,000 miles!

So, how do you know how long you can push your truck before coming in for an oil change? Should you rely on your maintenance light? Should you just pick a mileage limit and stick to it?

In order to determine a proper oil change interval for your truck, you’ll need to put on that lab coat and engage some real experts in oil and oil analysis. Today, we’re going to explore whether you should analyze your Duramax engine oil by going through some basics and answering some questions.

  • What Is Engine Oil?
  • Synthetic VS. Conventional
  • Fluid Analysis Kit

Curious about how to get the most from your engine oil? Let’s get into it.

What Is Engine Oil?

Even though the pendulum has generally swung in the direction of synthetics being superior to conventionals; both of these oil types are still found in Auto Parts stores all over the nation. For the Duramax engine, synthetic is recommended by not only the factory but also by the experts at Merchant Automotive as well. We’ll get into why that is down below in a second.

At its core, engine oil’s job is to lubricate the moving parts of your truck’s internal combustion engine to minimize friction, which is the enemy in any engine. Friction produces heat and heat wears out internal engine components quickly. This is where engine oil comes in.

Not only does it leave a slippery surface (reducing friction) on the surface of metal parts but it also transfers the heat produced from engine friction into the oil itself and as it is pumped through your engine via an oil pump, heat is then transferred into the oil itself. The oil then moves along to an oil cooler, where it is cooled by air as your truck moves along. This process repeats thousands and thousands of times a minute.

Over time, the oil begins to break down and loses its ability to retain heat and properly lubricate - leading to the need for an oil change.

Conventional VS. Synthetic

As far back as 1929, chemical companies began to experiment with man-made chemicals that could mimic the lubricating qualities of crude oil-based products, while mixing in additives that provided additional benefits to your engine. Although the base of synthetic oil is typically a closely guarded secret, it is widely believed that these products are distilled from crude oil, and are essentially created by breaking down the components of crude oil and carefully selecting the components that are beneficial for ultimate lubrication. This is oil evolution.

Synthetic oil was originally designed to be used in intense applications like spacecraft and jet - engines but over time, the technology got cheaper and manufacturers were looking for lubrication that would protect motors for the long haul, while also offering exemplary fuel economy characteristics.


Conventional oils are by comparison to synthetic oils, heavy, and viscous (thick) which are not beneficial to modern, high-torque motors like the Duramax. The energy required to move conventional oil through your motor robs your Duramax of both power and fuel - economy. It’s also inferior in high-heat turbocharged motors.

Under a microscope, you’ll see molecules of all different shapes and sizes in the engine oil. Conventional oil will have molecules of various sizes, while synthetic oil will show universally sized and shaped molecules. 

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Why does this matter to you and your Duramax? The choice is simple:

  • Superior Engine Protection
  • Less Sludge and Deposits
  • Better Viscosity
  • Superior Protection In Turbocharged Engines (Like The Duramax)
  • Super Long Oil Change Intervals

Fluid Analysis Kit

So, we know that synthetic is the clear choice in our trucks (if you’re not running it, this needs to change immediately!) but how do we know when to change the oil? This question is especially challenging because not every truck is used the exact same way or driven the same way by their owners! Some owners (you know who you are) are leadfoots who put their engine through its paces on a regular basis while hauling heavy loads, while some owners only tow a few times a year but daily drive their truck. Each of these driver profiles will have a drastically different set of requirements for when to optimally change out their synthetic oil.

We help you take out all the guesswork with the Merchant Automotive Fluid Analysis Kit! We’ve partnered with the Apex Oil Labs to provide a valuable service to Duramax owners that really want to know what’s going on with their engine oil. Simply provide a sample of your engine’s oil in the provided container and ship it to Apex labs for a full analysis. Once the lab receives the sample, they’ll typically have results ready in as little as one business day. This service is typically reserved for large-scale fleet operators but at Merchant Automotive we’ve made this a reality that our customers can take advantage of.

What’s Analyzed?

Your fluid analysis will involve a series of tests that monitor lubricant contamination, wear metals, and chemical composition:

  • Viscosity: A measurement of the fluid’s ability to flow at a specific temperature. Viscosity is one of the important primary characteristics of a lubricating fluid.
  • TAN: Total Acid Number, a chemical titration, to measure oil acidity. Higher TAN indicates a higher level of oxidation in oil.
  • TBN Retention: Total Base Number, a chemical titration, to measure the remaining neutralizing ability of the oil. Typically TBN should not be allowed to drop more than 50-65%, depending on factors, such as equipment type, fuel sulfur level, and oil consumption rate.
  • Contaminants: Glycol, fuel, soot, water, and particle (dirt) contamination can cause numerous problems and lead to catastrophic failures. Their presence can also be symptoms of active problems in the assets that are not lubricant-based.
  • Soot: Typically caused by reduced combustion efficiency, soot will increase engine wear especially in engines using EGR technology.
  • Coolant: One of the most destructive contaminants in engine oil, coolant can increase the viscosity of the oil, leading to issues such as boundary conditions, possible corrosion within the system, and plugged filters.
  • Fuel Dilution: Increased with the addition of emission-reducing equipment, fuel dilution leads to problems such as reduced viscosity, increased volatility, weakened lubricant detergency, corrosion, and more.
  • Wear Metals: Abnormal levels of certain metals are indicative of excessive component wear.
  • Other items such as nitration, oxidation, sulfation, and specific oil additive packages

Fluid Test Benefits

First and foremost, testing your oil can save you big money in the long run. Rather than perform fluid changes at predetermined intervals, fluid analysis will help you determine the appropriate fluid change intervals based on your individual usage and habits. This can add up to some serious money over the lifetime of your truck!

Testing your fluids can also help boost resale value by providing a potential buyer confirmation that your fluids are indeed in top condition and your internal components are ready to go the long haul. This can go miles when giving an extra boost of confidence to your buyers. Even if you have no intention to sell, tracking the internal wear of engine components can be crucial when you have high-mileage on your truck.

This level of testing allows you to be on top of your truck's needs at all times. For the hardcore owner, it’s simply a must.

What Other Fluids Can I Test?

Although we have been specifically talking about engine oil, you can actually test most fluids in your trucks and get a thorough analysis in just a few days:

  • Transmission fluid
  • Gear oil
  • Hydraulic oil
  • Engine coolant (Please use Merchant Automotive’s Coolant Analysis kit for coolant testing)

What Comes In The Kit?

  • Sample Bottle
  • Shipping Container
  • Fluid Analysis Form
  • Prepaid Return Shipping Envelope

What Types Of Vehicles Does This Work On?

Here’s the best part: you can do this analysis on ANY vehicle in your garage:

  • Passenger Cars
  • Heavy Duty Trucks
  • Motorcycle
  • UTV
  • ATV
  • Generators
  • Farm Equipment
  • Etc.

Trust The Duramax Truck Experts

We’ve partnered with Apex Oil Labs to bring you a level of visibility and analysis that is a true first in the world of Duramax trucks. This technology and analysis used to be reserved for commercial fleets but we’ve taken that barrier away for our customers. We don’t just sell parts for Duramax trucks, we sell fully engineered, science backed solutions to the most common problems our customers face on a daily basis. At Merchant Automotive, we’ve got your back and we're just as invested as you are when it comes time to getting your truck to go the distance.

This is what we do, everyday!