Buying a high-mileage used diesel pickup truck—whether it’s a Ford Super Duty Power Stroke, a Ram Cummins, or a Chevy/GMC Duramax—can be one of the smartest ways to get a seriously rad truck without paying that sickening new-truck price tag. The challenge comes when you see a truck with 200,000 or even 300,000 miles on the odometer. Used prices generally drop as miles rise, but many hesitant buyers wonder if that kind of mileage is too much and whether the truck will hold up.

Is It Worth Buying A High-Mileage Diesel Truck?

Indeed, high mileage on a diesel engine doesn’t automatically make it a bad buy—if it’s been maintained. Unlike gas engines, diesel engines are built for longevity. A well-cared-for diesel can run 300,000–500,000 miles. What really matters is the history of the truck, the maintenance it has received, and the condition of the key components that keep it running strong. Highway-driven miles with regular service are far less concerning than neglected trucks that pulled heavy loads every day.

How Many Miles Are Too Many On A Diesel Pickup?

It’s all about reputation when it comes to this question. Here are some general thoughts.

• Ford Power Stroke (6.7L): Solid beyond 200k miles when serviced. Earlier 6.0L/6.4L models need more caution due to EGR and head gasket issues.
• Ram Cummins (5.9L/6.7L): Known for extreme longevity. Many run 300k+ miles, but transmissions are often the weak link.
• GM Duramax (6.6L): Reliable into the mid-200k range. Watch for injector replacement history, as it’s a common and costly job.

In short, it comes down to condition, service records, and your mechanical ability.

Used Diesel Truck Reliability: Key Parts To Inspect

When buying a used Cummins, Power Stroke, or Duramax, make sure to know the status of these components:

• Fuel Injectors: Typically wear out around 150k–200k miles. Proof of replacement is a big plus.
• Turbocharger: Check for whining, smoke, or oil leaks. A healthy turbo is crucial for power.
• Transmission: Diesels put huge stress on automatics. A rebuilt or replaced transmission adds value.
• EGR System and Head Gaskets (especially 6.0L Power Stroke): Look for documented repairs or upgrades.
• Suspension and Steering: Expect ball joints, tie rods, and bushings to need attention past 150k miles.
• Rust and Frame: A solid drivetrain means little if the truck’s frame is compromised by rust.
• Interior: Notice the condition of the interior. It would be rather uncharacteristic for a truck to have a pristine interior and a neglected drivetrain.

Green Light: Buy A High-Mileage Diesel?

Is it worth buying a high-mileage diesel truck? Only hindsight knows for sure, but the answer is yes—if you take the time to evaluate it properly. A Cummins with 250,000 miles that has been carefully maintained may be more reliable than a neglected Power Stroke with half the mileage. Service records, replacement of major components, and a clean bill of health from a trusted diesel mechanic (maybe that’s you) are far more important than the number on the odometer. If the right boxes are checked, a used Duramax, Cummins, or Power Stroke can deliver years of dependable performance and save you tens of thousands compared to buying new. In the end, a well-cared-for high-mileage diesel pickup isn’t just okay to buy—it might be the smartest move you can make.