How Many Miles Will a 6.6 Duramax Last [+Maintenance Tips]

The 6.6 Duramax is a powerful diesel engine that has gained immense popularity among truck enthusiasts. It has been used in various models of Chevrolet and GMC trucks since its introduction in 2001. One question often arises among truck owners is how many miles will a 6.6 Duramax last?

What is the Life Expectancy of a Duramax Diesel Engine?

A well-maintained Duramax diesel engine can run up to 200,000 miles before requiring significant repairs. With proper maintenance and care, some Duramax engines have been known to last well over 500,000 miles. The lifespan of these engines ultimately depends on various factors such as usage habits, driving conditions, and regular maintenance practices.

How Many Miles Will a 6.6 Duramax Last?

The 6.6 Duramax is a popular diesel engine in heavy-duty trucks, including Chevy Silverado and GMC Sierra. 

It’s worth noting that General Motors offers a warranty of 100,000 miles or five years on their Duramax engines. This means the manufacturers expect the engines to last at least this long under normal driving conditions. Many owners have reported driving their trucks for over 200,000 miles with no major issues. 6.6 Duramax give you great Fuel Mileage.

Duramax Maintenance Tips:

Duramax Maintenance Tips

The 6.6-litre Duramax engine is one of today’s most powerful and reliable engines. Like any other machinery, it requires regular maintenance to keep it running at peak performance.

Here are some tips for maintaining your Duramax engine.

  • Make sure you change the engine oil and filter regularly
  • Use suitable oil and filters
  • To refill the diesel exhaust fluid, open the fuel DEF door (some vehicles need to open the hood to find the DEF door), remove the blue cap, and pour the DEF using a funnel
  • Wait for the fluid level to update on the DIC
  • Wipe away any spills
  • Place the cap back and close the fuel door
  • Change the fuel filter; follow the owner’s manual first because the location of the fuel filter varies from vehicle to vehicle.
  • ram 1500 bolt pattern
  • Before changing the filter, ensure your engine is turned off and the vehicle brake is applied.
  • Before changing the fuel filter, drain water from the filter.
  • Withdraw the filter element cap
  • Withdraw the old filter element & O-ring
  • Place the new O-ring around the cap and lubricate it
  • Install the new filter element into the housing
  • Place the cap back and tighten it
  • Prime the fuel filter
  • Reset the fuel filter life
  • Have the engine serviced regularly
  • And make sure you drive the vehicle regularly to keep the engine in good condition.

What to Look for When Buying a Used Duramax?

If you’re in the market for a used Duramax, there are a few things to remember before making your purchase. The Duramax diesel engine is known for its durability and power, but it’s important to research and make an informed decision.

Checking Cooling Pressure:

To check the cooling system pressure, inspect the radiator for any visible signs of wear or damage. You should also look for any leaks or cracks in the hoses that connect the radiator to other components in your engine bay. Once you’ve inspected these areas, it’s time to test the pressure itself.

You’ll need a specialized tool called a cooling system pressure tester to do this. This tool lets you pressurize your cooling system and check for leaks or issues with your hoses, gaskets, or other components.

The cooling pressure should be between 15 to 25 psi.

Checking the Engine Oil:

Checking the Engine Oil

To begin, inspect the oil level and condition. The oil should be appropriate on the dipstick and free from contaminants like metal shavings or coolant. Examine the color of the oil; if it appears dark or burnt, this could indicate that it hasn’t been changed regularly or has been subjected to high temperatures. 

Checking Engine Codes:

To check the engine codes, you’ll need an OBD-II scanner. These can be purchased online or at your local auto parts store. Once you have the scanner, plug it into your vehicle’s diagnostic port (usually under the dashboard). The scanner will then display any error codes in the system.

If no error codes are present, that’s a good sign that the vehicle has been well-maintained and is in good shape.

Injector Balance Rate:

All injectors should have similar flow rates within 4-6% of each other. If one or more injectors have significantly different flow rates, it could indicate that they need to be replaced or that other engine problems are causing uneven fuel distribution. 

Check the Drivability:

During your test drive, pay attention to any unusual sounds or vibrations from the engine or transmission. These could be signs of underlying issues that may require costly repairs. Check for any warning lights on the dashboard indicating problems with key systems such as brakes, steering, or suspension.

Check the 4WD System:

The 4WD system provides additional traction and stability when driving off-road or in slippery conditions. To ensure the 4WD system is in good working condition, take the vehicle for a test drive on rough terrain and listen for unusual noises or vibrations.

Listen for a Hissing Noise:

A hissing noise can indicate that there may be an issue with the vehicle’s turbocharger system, which can lead to costly repairs down the line if not addressed promptly.

Check the Brake Pad Wear:

Check the Brake Pad Wear

Inspecting the brake pads will show you how much they have worn down and whether they need replacing soon. A general rule of thumb is that if the pads have less than 1/8 inch left, it’s time for a replacement. Uneven pad wear can indicate problems with calipers or rotors, which can become costly.

Exhaust Noise:

Start by listening carefully to the engine as it idles and accelerates. Any abnormal noises, such as hissing or rattling, could indicate an issue in the exhaust system. Take note of any changes in engine performance that occur when you apply throttle – this may also indicate problems with the exhaust.

Cummins Vs Duramax, Which One is Better?

The Cummins and Duramax engines are two of the most popular on the market regarding heavy-duty pickup trucks. Cummins Inc. manufactures the Cummins diesel engine, whereas the Duramax diesel engine is a joint venture between General Motors and Isuzu Motors. Both engines have unique features, advantages, and disadvantages, so choosing one can be daunting for truck buyers.

Let’s discuss them separately.


Cummins Inc. is a global power leader that designs, manufactures and distributes engines, filtration and power generation products. Founded in 1919, this American multinational corporation has provided innovative solutions to its customers for over a century. Cummins employs approximately 62,600 people worldwide and serves customers in more than 190 countries.

The company’s innovative approach to engineering has led to the development of some of the most powerful and efficient engines on the market today. Its diverse range of products includes diesel and natural gas-powered engines for trucks, buses, RVs and marine applications, as well as industrial generators for use in data centers, hospitals and other critical facilities.

In the case of history and experience, Cummins is in a leading position.


Duramax is a brand of diesel engine that has won the hearts of many truck enthusiasts thanks to its power, fuel efficiency, and durability. The Duramax engine was developed by General Motors (GM) in partnership with Isuzu Motors in Japan. The first Duramax V8 engine was introduced in 2001 and has undergone several upgrades.

The latest version of the Duramax engine, the L5P, is found in GM’s heavy-duty pickup trucks like the Chevrolet Silverado 2500HD and GMC Sierra 2500HD. It boasts impressive performance figures such as 445 horsepower and 910 lb-ft of torque. It’s designed to meet stringent emissions regulations while providing excellent fuel economy, making it an attractive option for fleet managers.

The Ultimate Decision Between Duramax vs Cummins:

Durability has always been a strong point for Duramax engines. These engines are built tough with sturdy materials that can withstand extreme conditions without breaking down. They also come equipped with advanced engineering technology that helps improve fuel efficiency and reduce emissions – important in today’s world, where environmental concerns are rising.

Performance is another area where Duramax shines compared to Cummins. With its impressive horsepower and torque output, this engine can deliver unmatched power for any job or task you may have at hand.

Durability and performance keep Duramax slightly ahead.

Is a Duramax Worth It?

The answer lies in your specific needs and budget. The Duramax engine investment will undoubtedly be worth it if you’re looking for a reliable workhorse that can easily haul heavy loads over long distances. The power-packed engine offers up to 910 lb-ft of torque, making it ideal for towing large trailers to haul cargo without sweat. Its impressive fuel economy means you’ll save on gas while enjoying top-notch performance.


At the start, we questioned how many miles will a 6.6 Duramax last. And the 6.6 Duramax engine has proven to be a reliable and durable powertrain with a long lifespan. With proper maintenance and care, it can easily clock over 300,000 miles or more before requiring major repairs.

Driving style and usage can also significantly affect the engine’s longevity. It’s important to keep up with regular maintenance schedules and pay attention to any warning signs of potential issues.


How many miles will 2008 6.6 Duramax last?

The 2008 6.6 Duramax diesel engine has a reputation for being incredibly reliable and durable. With proper maintenance, it can last for hundreds of thousands of miles. Many owners report that their engines have lasted up to 400,000 miles or more without major repairs. 

How many miles will an LBZ Duramax last?

An LBZ Duramax can last between 250,000-400,000 miles depending on how well it is maintained and the type of driving conditions it is exposed to. Regular oil changes and other preventative maintenance measures will help ensure the engine lasts as long as possible. 

How long will an LLY Duramax last?

The LLY Duramax engine is a 6.6-litre diesel engine manufactured by General Motors from 2004 to 2006. This engine was designed to last at least 250,000 miles with proper maintenance and care. The actual lifespan of an LLY Duramax can vary depending on how well it has been cared for and maintained. The engine could last up to 400,000 miles or more if it has been maintained properly. 

How many miles on Duramax before rebuilding?

You can expect a Duramax diesel engine to last between 150,000-300,000 miles before needing to be rebuilt. With proper maintenance and care, some engines can reach 400,000 miles or more before needing serious repairs or replacement parts.

Is the Duramax diesel a good engine?

Yes, the Duramax diesel is a good engine. It is a 6.6-litre turbo-diesel V8 engine that was first produced by General Motors in 2001. The Duramax diesel has proven reliable and efficient, offering great performance and fuel economy. It is also very durable and can last up to 300,000 miles with proper maintenance. 

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