Top 6 Duramax Years To Avoid and Why

Duramax is one of the leading diesel engine manufacturers. You’d find Duramax engines in Chevy trucks, SUVs, and other vehicles from General Motors. Inarguably, Duramax engines are reliable, sturdy, and fit for any task you’d require a diesel engine to do.

The first Duramax engine was introduced in 2001, and there have been several models produced to date. While Duramax engines are reliable and strong, not all of them are really what buying. That said, what are the Duramax years to avoid?

Actually, it’s quite tricky to mention the worst Duramax years, but the first models produced between 2001 and 2004 are too old and synonymously linked with many problems due to their inability to adapt to modern diesel engine demands.

This article navigates through all Duramax engine model years and how they perform. So you can have a clear view and choose the Duramax year you think is best for you – to cope with.

Duramax Engines Overview

Duramax is a diesel engine line by DMAX, a company co-owned by Isuzu and General Motors. The engines are built as V8 or in-line straight six-cylinder engines – all diesel-powered.

You’d find Duramax engines installed in General Motor trucks produced under the Chevy brand. The Duramax engines are represented by codes: LB7, LLY, LLY/LBZ, LMM, LGH, LML, L5P, and L5D.

Duramax LB7 was the first model produced from 2001 to 2004; it produced around 300 hp and 520 lb-ft of torque. In mid-2004, LLY models took over.

Over the years, there have been nine (9) Duramax engine models, with the latest models being L5P and L5D. All Duramax engines are built ready for demanding applications, but sadly, not all of them are worth getting on your truck.

What Are The Duramax Years To Avoid?

When you check on fora and user reviews about different Duramax engines, you will notice that while some people criticized certain model years, other people allege that those model years were the best for them.

What does this imply? It means that how you use and maintain your Duramax engine plays a huge hole in determining its durability.

Hereunder are Duramax model years and the most common problems you may most likely experience with each year.

  1. 2001 – 2004 LB7 models: Parts are expensive to replace and typically have injector issues
  2. 2004 – 2005 LLY models: Overheats too much, probably one of the reasons it is short-lived
  3. 2006 – 2007 LBZ models: Some models do overheat, and the pistons are poorly-made and always fail/break down easily
  4. 2007 – 2010 LMM models: No really serious issues, and these Duramax engines come with DPF systems
  5. 2011 – 2016 LML: Built with DPF and DEF systems and uses CP4 injection pump instead of CP3; there are not many problems reported for these Duramax engine models
  6. 2017 to Date L5P: L5P is pretty much all new

Yeah, not all Duramax engine series was mentioned above; these ones are the most “talked about” series in forums. The very worst Duramax engines were the LLY models made between 2004 and 2005.

Duramax LLY engines were meant to be an upgrade to the LB7, but they flopped more than the LB7 models. However, Duramax LLY offered more power and better fuel economy than the LB7s; they were also the first Duramax engines with an EGR valve and a variable vane turbocharger.

The most common problems with the LLY models included head gasket failures and fuel injector issues. The head gasket problem led to constant overheating of the LLY engines, and fixing the problems typically costs more than a grand.

Best Duramax Years To Buy

Skip the first models from 2001 to 2004; they are too old and weak; also, skip the 2004 – 2005 LLY models; the rest are practically good to buy.

In other words, Duramax models from 2006 to date are reliable and recommended among the best years to buy. If you need a more powerful model, you should pick from the LML series upward.

Frequently Asked Questions

How Can You Make a Duramax Engine Last Longer?

Change the oil at the right time, replace faulty parts with new, original ones, and always go for servicing when due; these are some of the simple things you can do to make your Duramax engine last longer and still deliver optimal performance.

What Are Duramax Engine Common Problems?

Head gasket failure, fuel injector problems, connecting rod failure, turbocharger issues, and DEF failures are some of the commonly reported issues with Duramax engines. These problems occur at random intervals and may cost up to a thousand dollars to fix.

Which Cars Have Duramax Engines?

You’d find Duramax engines in vehicles built by General Motors or any brand it owns (Chevy, GMC, and others). Duramax engines are available in Chevrolet Silverados, GMC Sierras, Chevrolet Kodiak, GMC TopKick, Chevy Express, GMC Savana, and many other vehicles built for off-road touring. Mostly, the Duramax engine is included as an option (but it is standard on certain trims).


Summarily, 2001 to 2005 are the worst Duramax years to avoid because they had a lot of problems. The best Duramax years are from 2007 upwards, while the 2007 to 2010 model years had the best engines – best for the money and best in performance.

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