Though the Duramax engine is a reliable name in terms of power, efficiency, and durability, not all models deliver satisfactory performance. So if you want to get the expected performance from the engine, you must know what is the best Duramax engine. Many automobile experts prefer LBZ 06-07 as the overall best Duramax engine.
Article Summary
So, What is The Best Duramax Engine?
It can vary in terms of engine features, vehicle types and the way it is taken care of. Read on to understand the best Duramax engine on certain aspects and get the best model years to check and worst years to avoid.
Below are various types of Duramax engines in terms of their best features:
1. Complete Stock
LBZ 06-07 is the best Duramax engine to be left fully stocked and driven. This engine is pre-DPF, eliminating the need for regeneration cycles. The engine also has an EGR system and catalyst.
2. Heavy Towing
L5P 17 to current and LML11-16 are the best Duramax engines for towing heavy objects for long distances. These engines have extreme power and superior chassis than older models. L5P is also a fairly new engine and doesn’t have any major issues.
3. Best for Modification
If you need the best engine to build a powerhouse off, pick the LB 01-04. To make this engine able to support extreme needs, you may need to take care of some parts including the injector and head gasket or valve cover gasket issue.
4. Flexibility
LML 07.5-10 and LLY 04.5-06 are the best Duramax engines for flexibility. The LLY has the largest turbo. However, this engine may overheat and cause head gasket issues over time. The LML is quite the same as the LBZ, however, it has DPF and increased HP to deliver excellent performance. The engine may show some trouble with DEF and DPF which is common for all vehicles from this era.
5. Durability
If you prefer a durable engine that doesn’t have any emissions devices like DPF, opt for the LBZ engine. This engine delivers increased horsepower and is perfect for heavy-duty use after doing some minor modifications like changing the cold air intake.
The LBZ and LLY have a 2006 crossover year. So, you can choose LLY 2006 instead of LBZ. However, LLY parts can’t be replaced. To determine the compatibility, check the trans. The 6-speed Allison refers to LBZ while the 5-seed is LLY.
6. LBZ 06-07 Duramax Engine
Many automobile experts considered the LBZ 06-07 the best Duramax engine and they have some logic. This engine doesn’t have injector problems like 2001 models nor overheat too much like the 2004 counterparts. So the engine saves significant money that may cost an expensive repair. LBZ 06-07 engine also doesn’t have much emission problems. This engine is also worth buying in terms of the engine reliability.
However, the pistons of this engine tend to crack particularly during providing output higher than 60 rare HP. This engine is also quite expensive and the best engine tag can be one of the reasons. Still, the 06-07 Duramax engine is worth the money particularly if you prefer an engine with fewer problems and that lasts for decades.
Best Duramax Engines Model Years To Check
The best Duramax engine model years to buy:
- Duramax LGH 2010 – 2017
- Duramax LML 2011 – 2016
- Duramax XLD25 2011 – 2021
- Duramax XLD28 2012 – 2021
- Duramax LWN 2014 – 2021
- Duramax L5P 2017 – 2021
- Duramax LM2 2019 – 2021
Since 2001, GM Authority has produced 11 different types of Duramax engines. Including four–, six–, and eight-cycle cylinder options in I or V configurations. However, not all types and model years of the Duramax engine are reliable and safe to buy.
Duramax engine had changed significantly in 2011 and included new emissions regulations. Though it makes the engine more complicated, it hugely increases the engine’s reliability. If you prefer the safest engine, opt for the models produced between 2011 and 2021.
It means you can choose LML, LGH, LWN, XLD25, LM2, L5P, and XLD28. These engines are designed with a urea injector feature and diesel exhaust fluid, resulting in better emissions. The after-treatment system of these engines also helps provide increased fuel economy.
However, these engines come with weak tie rods that may go bad due to frequent off-roading, drag racing and sled pulling. The diesel particulate filter of this engine also causes failure.
Worst Duramax Engine Model Years to Avoid
The worst Duramax model years are:
- Duramax LB7 2001 – 2004
- Duramax LLY 2004 – 2005
- Duramax LBZ 2006 – 2007
- Duramax LMM 2007 – 2012
In short, you should avoid the older Duramax engine that was produced between 2001 and 2010. The newer models provide more improved performance. GM Authority first produced a 6.6L Duramax engine that was used in the GMC Topkick, Chevrolet Silverado, 2001 – 2004 Chevrolet Kodiak, and GMC Sierra HD. The engine lacked exhaust gas recirculation or diesel particulate filter.
LB77 is another model that you should avoid as it causes problems with the fuel injection system. The Duramax engine usually comes with GMC Sierra HD, Chevy Silverado, Chevy Kodiak, or GMC Topkick.
Duramax LLY engine comes in Hummer H1, 2004 – 2005 Chevrolet Silverado, and GMC Sierra HD, which gets overheated during heavy towing. Some owners complain its head gasket is blown out.
Though the LBZ engine addressed the blown gasket and overheating issue, its piston cracks at higher HP. Some owners also complain that its rocker panels and cab corners rust out quickly in northern areas due to salt and high humidity.
The LMM engine is fitted in Chevrolet Silverado, Savanna, Kodiak, GMC Topkick, and Sierra HD which causes cracked pistons at higher HP. Its DPF also contains a failure point.
Expected Longevity of Duramax Engine
Duramax engines are extremely reliable by default and last thousands of miles with proper maintenance. You can see lots of classic vehicles on the roads that still work great even after passing thousands of miles. Some users even experience that Duramax diesel engines reach up to 200,000 miles without showing any issues.
So with proper care, your engine may run around 400,000 miles. It isn’t also rare that a Duramax diesel engine can run up to 535,000 miles. However, on average, you can expect around 200,000 and 300,000 miles longevity of the Duramax engine before experiencing any major issues.
However, the exact longevity of a diesel engine varies depending on the vehicle’s make and model years, driving style and skill as well as the amount of maintenance.
FAQs
Is LB7 Better Than LLY?
The LB7 is a better Duramax engine in terms of emission controls while the LLY engine has the largest turbocharger. The LBZ also gets plenty of improvements including increased power while the LMM engine includes a diesel particulate filter.
Is General Motors Discontinuing the 3.0 Duramax Diesel?
GM’s 3.0 turbo diesel Duramax engine comes in the 2023 Chevy Suburban, 2023 Chevy Tahoe, 2023 Cadillac Escalade, and 2023 GMC Yukon. However, the manufacturer stated that these vehicles won’t launch with a 3.0L Duramax engine anymore.
Why is Duramax Better Than Cummins?
Duramax engine comes with a maximum of 445HP while Cummins has up to 420HP. Horsepower is a vital consideration particularly if you have a heavy-duty vehicle. In this case, the Duramax engine is better than the Cummins engine.
Final Words
Hope now you understand what is the best Duramax engine. Simply avoid the model years that have reduced reliability and get too many complaints from trusted sources. Make sure the model year you are choosing meets your certain needs, matches the driving style, and has a higher reliability score.
Lastly, maintain your Duramax diesel engine properly and inspect it by an expert mechanic periodically to get the most out of the engine.
