6.6 liter Duramax engine specs, issues and overview - Skoolie Engine (2023)

General Motors and Isuzu formed a joint venture called DMAX to produce a family of 6.6-liter Duramax V8 diesel engines for Chevrolet and GMC pickup trucks, beginning with the 2001 model year. Over the past two decades, the joint venture has had six variants produces the Duramax diesel engine, including the 6.6L Duramax L5P diesel engine, which is still in production today.

This guide to the Duramax 6.6 liter diesel engine is part of oursDiesel Engine Guideto help seriesbuy a school bus.

This article covers the 6.6 liter Duramax engine including:

• engine overview
• engine specifications
• towing capacity
• Life expectancy
• maintenance requirements
• Transmissions usually paired
• general engine problems
• engine comparisons with6,0 L Krafthubmi6,7 L Krafthub

6.6 Summary of the Duramax engine

(Video) 2021 Chevrolet 3.0L Duramax turbo diesel engine Overview

Variants of the 6.6 liter Duramax engine have been developed with different components required to meet global emission reduction regulations while maintaining and even increasing power and torque over time. Since the first model year, the engines have become popular options for General Motors pickups, vans and medium-sized trucks.

Like the original Duramax model, the 6.6-liter Duramax LB7 diesel engine was released in 2001 for the Chevrolet Kodiak, Chevrolet Silverado, GMC Topkick and GMC Sierra HD pickups. It became a popular aftermarket choice due to a lack of emission control parts, which were often blamed for engine problems on later models. The 32-valve design featured an experimental composite cylinder head and a Bosch high-pressure common-rail direct injection system that reportedly had problems. Production of this variant ended in 2004.

The second diesel engine model called 6.6L LLY Duramax debuted in 2004. It was almost identical in components to its LB7 predecessor and lacked modern emission control parts. GM fixed problems with the fuel injectors found in the previous engine model, but this variant reportedly had overheating issues when towing heavy loads or driving in high temperatures. The engine only survived one model year for the Hummer H1 Alpha, Chevrolet Silverado and GMC Sierra HD trucks. Production ended in 2005.

The third diesel engine model called 6.6L LBZ Duramax was launched in 2006 for General Motors Express and Savanna pickups. It was also installed on other trucks including Chevrolet Silverado HD, Chevrolet Kodiak, GMC Sierra HD and GMC Topkick. It is considered by mechanics to be the best model in the Duramax diesel range, as it had no problematic emissions control parts and featured a new Allison six-speed gearbox. General Motors corrected the flaws found in earlier engines (namely improved materials for bearings and cylinder blocks) and in the process managed to increase power and torque. Changes from previous models included a revised piston design, a thicker connecting rod section, all-new fuel injectors, a revised variable geometry turbocharger and an all-new E35 controller to increase fuel flow. However, it was known to have problems with a factory lift pump. Production ended in 2007 when stricter emissions regulations came into force.

The fourth diesel engine model called 6.6L LMM Duramax debuted in 2007 and was almost identical to its predecessor LBZ Duramax. The difference was new emission control parts to meet then-tightening US air quality regulations. The 6.6 liter Duramax LMM has been fitted with an even more efficient variable geometry turbocharger system, improved exhaust gas recirculation (EGR) and closed crankcase ventilation to reduce nitrogen oxides (NOx). Additional emissions control came from a new diesel particulate filter (DPF) to reduce soot and particulates. The diesel engine powered the Chevrolet Express, GMC Savanna, Chevrolet Silverado HD, GMC Sierra HD, Chevrolet Kodiak and GMC Topkick. The engine was known for cracking problems with its pistons. Production ended in 2011.

The fifth diesel model, dubbed the 6.6L LML Duramax, was introduced in 2011 with improved emission controls for the Chevrolet Silverado HD and GMC Sierra HD trucks to meet even more stringent air quality standards. The diesel engine was also able to reduce sonic vibration and increase power/torque by increasing fuel system pressure. However, these component changes contributed to a problem with the injection pump. Production ended in 2016.

The sixth model, called the 6.6L L5P Duramax, was launched in 2017 and is still in production today for the Chevrolet Silverado HD and GMC Sierra HD trucks. It is considered to be the best post-emission Duramax engine as previous problems with the injection pump and exhaust systems have largely been corrected. The 6.6-liter Duramax L5P offers a smoother ride with more horsepower, torque (445 hp and 910 lb-ft of torque) and horsepower ratings than previous versions of the engine. In 2020, an Allison 10-speed automatic replaced the aging Allison 6-speed automatic.

Motormodelle 6.6L Duramax

6.6 Duramax transmission

The Allison 1000 transmission has been the standard automatic transmission for 6.6 liter Duramax diesel engines since the introduction of the first model (LB7) in 2001. Early engines were fitted with 5-speed automatic transmissions, and the 6-speed automatic transmission was introduced in the later models (from model year 2006 LBZ). In 2020, the old 6-speed automatic transmission was replaced with an Allison 10-speed automatic that further reduces torque in the lower gears.

Trailer with Duramax 6.6

The best towing capacity is offered by the 6.6 liter Duramax L5P diesel engine. Chevrolet and GMC HD Trucks (2017-2019 model years) with L5P Duramax have a maximum towing capacity of 23,300 pounds. In 2021, the towing capacity increased to 36,000 pounds.

6.6 Duramax Motor Life Expectancy

The Duramax 6.6 liter diesel engine is sold with a 100,000 mile guarantee. Mechanics report that with proper maintenance, the engine can survive up to 200,000 miles.

6.6 Duramax engine maintenance requirements

Maintenance is key to avoiding frequent breakdowns.

Common problems with 6.6 liter Duramax engines

Mechanics report that the best 6.6-liter Duramax diesel engine was the first LBZ model, although other models are relatively reliable and durable. Mechanics report that the most problematic models were the 6.6-liter LLY and LML diesel engines.

• Problem with the fuel system- In general, the Duramax 6.6 liter diesel engine uses an injection pump instead of a suction pump and this can damage the fuel filter housing. The engine is known for two fuel-related problems. First, air can get into the fuel lines. Second, this reduces the amount of fuel going through the engine.
  
• Problem with the water pump– On average, the water pump should last more than 100,000 miles, but mechanics report that it usually needs to be replaced after 80,000 miles. The LB7 model water pump has been known to leak. Water can leak out of the bottom of the pump and you'll need a good extractor to get it out.

• overheating problems– If the water pump fails, the Duramax 6.6 liter diesel engine will overheat. A common problem on 2005 and earlier models is fan clutch failure, which can cause the engine to overheat, especially in hot weather.
  
• Problems with injectors- The 6.6-liter Duramax is notorious for injector failures. On the 2001-2004 LB7 models, two major issues are internal cracking and corrosion. Later engine models used tougher materials and longer injector life.
  
• cracked pistons- This issue is most noticeable on the LBZ and LMM 6.6 liter Duramax models. The failure is mainly due to poor quality castings. The cast aluminum piston is split along the center of the gudgeon pin. Most scenarios occur at power levels well above 600 hp.

• broken crankshaft– The error occurs most frequently in all generations of high-horsepower engines and is not model year specific. The crankshaft usually breaks near the first connecting rod bearing due to a combination of over-revving and a large external counterweight.
  
• curved rods– High-horsepower Duramax models LB7 and LLY 6.6L can stress pistons, connecting rods and crankshaft. The bars are the weakest link, despite being made of forged steel. Mechanics report that they can bend long before they break.

GM 6.6L Duramax gegen Ford 6.7L Powerstroke

General Motors' line of 6.6 L Duramax diesel engines had been in production for a decade. Ford introduced its own 6.7 liter Power Stroke diesel engine for Super Duty trucks in 2011. During this time, GM was able to solve mid-series emissions problems. years of production. Choosing a diesel engine can boil down to brand loyalty.

Ford had a long-standing lead in the US truck sales race with GM and other vehicle brands. The Ford 6.7L is the fourth generation of the Power Stroke family of diesel engines, but it is the first of these engines to be built in-house by Ford. Ford was able to reduce warranty/recall losses on the Navistar International engine (6.4L and 6.0L Power Stroke engines) and gain a competitive advantage in the growing diesel segment by increasing its developed, designed and manufactured its own diesel engine.

Starting with a clean sheet, Ford engineered the 6.7-liter, 8-cylinder, overhead valve (OHV) Power Stroke diesel engine with aluminum cylinder heads, cast aluminum pistons and a compressed graphite iron block. Over a decade of production, Ford has continued to update and refine the 6.7-liter Power Stroke diesel engine through three generations. The third generation Ford Power Stroke 6.7 liter diesel engine was introduced in 2020 and is still in production for model year 2022 Ford Super Duty trucks. It features a new steel piston design, revised variable geometry turbocharger, updated cylinder head and a new fuel injection system.

GM 6.6L Duramax vs 6.0L Powerstroke

The 6.6 L Duramax diesel engine was introduced for Ford Super Duty trucks, vans and SUVs a few years before Ford Motor Company and Navistar International released the 6.0 L Power Stroke diesel engine in 2003. Like later models of the 6.6-liter Duramax, the 6.0-liter power-stroke diesel engine was developed by Navistar International in response to tightening emissions regulations.

The 6.6 liter Duramax experienced engine problems in several versions, but not to the same degree as the 6.0 liter Power Stroke engine. Despite advanced technology, the 6.0L Power Stroke Diesel engine was considered to be one of the more problematic engines in the Power Stroke Diesel engine range. Many of the problems with the 6.0L Power Stroke diesel engine stem from emissions systems and/or lack of maintenance. Ford eventually terminated the manufacturing partnership with Navistar International due to extensive recalls and warranty costs for the 6.0-liter diesel engine.