September 8, 2020

What is Considered High Mileage for a Diesel Truck?

Written By: ProSource Diesel

Diesel pickup trucks often get higher mileage than gas trucks thanks to having more durable engines that can withstand higher compression ratios. Even when used extensively for towing and hauling, Powerstroke, Cummins and Duramax diesel trucks typically last well beyond 100,000 miles. Because of that, it’s not uncommon to see diesel pickups with 200,000 and even 300,000 miles commanding good resale values on the used truck market. Drivers looking for a used diesel pickup usually know that high mileage doesn’t mean the truck’s life is over.

Diesel Truck vs. Gas Truck Lifespan

With modern trucks lasting longer than ever, it’s not unusual to find gas trucks with lifespans over 200,000 miles. However, diesel pickups can go above and beyond that number. Diesel pickups often last 500,000 miles and more. And it’s not just their engines that are sturdier. Diesel truck bodies themselves are built to be more durable because diesel engines are heavier than gas engines, so the trucks are designed and constructed to be tougher.

Not All High Mileage Is Equal

As with other vehicles, not all high mileage diesel pickups are the same. For example, a diesel pickup used extensively for towing and hauling heavy loads for 100,000 miles might be in need of some major repairs while a lightly used diesel pickup with 200,000 miles on the odometer might still have years of trouble-free life ahead. But it’s also important to remember that there are a number of other factors besides just the number on the odometer that determines the life expectancy of a diesel truck such as:

  • Maintenance records
  • Current condition
  • Number of owners
  • Primary use
  • Accidents

For example, a diesel pickup with 200,000 miles or more that has only had one or two owners and has good maintenance records is likely to be a better bet than a 100,000-mile truck with four owners and few records.

The truck’s overall condition and appearance are also important. A truck with a well-maintained exterior and interior is likely to have been well maintained mechanically as well.

What Is Considered High Mileage for a Duramax Diesel Pickup Truck?

Duramax is the brand of diesel engine found in trucks made by General Motors which includes GMC trucks and Chevy trucks. Opinions vary about what is considered high mileage for these engines. Some owners say that 100,000 for Chevy diesel trucks is high mileage, while others say that nothing under 350,000 should be considered high mileage. A poorly-maintained engine can quickly fall into disrepair before it even reaches the 100,000-mile mark while a well-maintained Duramax pickup truck should last 400,000 or even 500,000 miles.

What Is Considered High Mileage for a Cummins Diesel Pickup Truck?

Cummins is the brand of engine found in the Dodge diesel and Ram diesel truck lines. Like the Duramax, Cummins diesel engines can be expected to last a long time. Between 350,000 and 500,000 miles is usually considered high mileage on a Cummins diesel. Of course, it again depends on how well-maintained the engine is.

Although it’s important to maintain the engine, some diesel pickup drivers say that it’s even more important to keep the truck alive around the engine because it’s more likely that the truck itself won’t last more than 500,000 miles even though its well-maintained diesel engine could.

What Is Considered High Mileage for a Powerstroke Diesel Pickup Truck?

The Powerstroke engine is found in Ford trucks and, like the Duramax and Cummins engines, can often last up to 500,000 miles. However, as with the Duramax and Cummins engines, between 350,000 and 500,000 miles is usually considered high mileage for a Powerstroke engine. Maintenance of the truck and the engine is the key to getting the most miles. It’s worth noting that Ford trucks are the most popular truck brand in America and are well-known for their overall reliability.

Considerations for Buying a High Mileage Diesel Truck

Buying a diesel pickup truck with 250,000 miles or more might be a great deal. Brand new diesel pickups tend to have higher price tags than their gas brethren, so buying used often makes a lot of financial sense. Consider the following when buying a used diesel pickup:

  • Check for service documentation to ensure the engine has been well maintained
  • Perform an engine and transmission service immediately after purchasing
  • If the engine checks out, inspect the chassis thoroughly
  • Service the drivetrain
  • Switch to a synthetic engine and gear oil
  • Inspect the cooling system
  • Remember that certain engines have specific problems

What About Oil Leaks?

Engines with high mileage often have oil leaks and it’s not always something to be alarmed about. Small leaks around gaskets and seals are not uncommon. For example, a bit of oil seepage around the front and rear main seals isn’t all that alarming and is even expected. On the other hand, oil more heavily coating the area around a seal or gasket might raise a bit more suspicion. It depends on how much oil is covering that area. In other words, while no oil leak is obviously preferable, the presence of a small oil leak on a high-mileage diesel engine shouldn’t necessarily be a deal-breaker.

Diesel Truck Fuel Additives

It’s a good idea to start a fuel additive regimen when buying an older diesel truck that has a mechanical injection system. Long-term operation of one of these older diesel engines without additional lubrication can cause early injection pump failure. But a fuel additive can help modern diesel engines as well. Additives can help increase the gas mileage of any diesel engine, whether it’s high-mileage or not.

Research Specific Diesel Engines and Trucks

As with any vehicle, different trucks and different engines have different problems. Buying a particular engine model that appears to have the least amount of problems might not matter if the truck it’s in has problems. Along with the engine’s problems, it’s important to research the specific truck’s issues as well. This is where maintenance records can be invaluable.

For example, it might be relatively common for the water pump in a certain truck to fail every 100,000 miles or so. A truck with 300,000 miles might be in great condition, but if the water pump hasn’t been replaced for 150,000 miles, you may be looking at costly repairs.

Why Use Synthetic Oil?

It’s never too late to start using synthetic engine and gear oil on a high-mileage diesel truck. Synthetic oil offers the following benefits:

  • Better extreme low and high-temperature performance
  • Improved chemical stability
  • Resistance to mechanical force breakdown
  • More resistance to oil breakdown from heat
  • Improved resistance against oxidation and sludge

The biggest enemies to oil stability are heat, repetitive mechanical forces and chemical breakdown from fuel dilution. Higher-mileage engines are more susceptible to all of these forces. Synthetic oil can extend the life of a high-mileage diesel engine and increase its efficiency.

Ultimately, synthetic oils reduce friction better than traditional oil. As mechanical parts wear out in high-mileage engines, friction can become greater. More friction means more heat, which further breaks down oil and diesel truck parts.

Summary

In conclusion, there is no single number for what is considered high mileage for a diesel pickup truck; however, in general, anything over 500,000 is usually considered high mileage. But always keep in mind that there are many more considerations in buying a used diesel pickup than mileage. A well-maintained high-mileage Powerstroke, Cummins or Duramax diesel pickup truck is often a better bet than a poorly-maintained and heavily-used diesel pickup with lower mileage.

Is your truck in the high-mileage category? You can count on ProSource Diesel for all your diesel truck parts and accessories regardless of which diesel truck you have. You’ll find a wide range of Cummins diesel parts, Duramax parts, and Ford diesel parts available on our website. ProSource is where repair shops shop for reliable and hard to find diesel parts and kits.

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