Got Chevy Diesel Truck that Needs Repair?

Bigg Boy Auto in West Palm Beach, FL specializes in Chevy Duramax Diesel truck service and repair. Our expert Chevy truck mechanics can handle any size engine and offer a great alternative to the dealer. Our staff knows Chevy inside and out and fix almost any problem with Duramax LB7, LLY, LBZ, LMM, LGH, and LML permanently.

Got Chevy Fuel Injector problems or performance issues? No problem! Our trusted mechanics have fixed it all. Call us today to speak with one of our Chevy expert mechanics Phone: 561-722-3299

The Bigg Boy Difference

Many other repair shops have a hard time diagnosing and fixing problems related to Chevy Trucks. Often it is difficult to find qualified mechanics that are willing to work on your diesel engine. This is because diesel engines are slightly more complex than regular gas-powered engines. Our mechanics are skilled professionals and will do whatever it takes to make sure you get your best performance worth out of your Chevy Truck.

The Duramax is a General Motors diesel engine family for trucks, designed by GM and Isuzu. The 6.6-liter Duramax is produced by DMAX, a joint venture between GM and Isuzu in Moraine, Ohio. The Duramax block and heads are poured at The Defiance GM Powertrain foundry in Defiance, Ohio. This engine was initially installed in 2001 model year Chevy and GMC trucks and has been an option since then in pickups, vans, and medium-duty trucks. In 2006, production at Moraine was reportedly limited to approximately 200,000 engines per year. On May 9, 2007, DMAX announced the production of the 1,000,000th Duramax V-8 diesel at its Moraine facility.

Common problems associated with the Duramax engine.

  • Fuel Starvation and/or Air in the Fuel Lines
  • Overheating
  • Injector Failure
  • Injector Harness Chafing
  • Glow Plug Failure/Concerns
  • Aluminum Cylinder Heads
  • PCV Design
  • Turbocharger Oil Ingestion
  • Allison 1000 Transmission Limp Mode
  • 2011 LML DEF/SCR System Woes

RPO LB7 (engine code “1”) was first introduced in 2001 and continued until early-2004. It is a 32-valve design with high-pressure common-rail direct injection and an experimental composite design cylinder head. The most common issue with the LB7 is injector failure, so common that a special policy bulletin was issued (#04039B). Fuel leaked and entered the crankcase, causing oil dilution. Early on, customers came forward complaining of severe overheating, and in some situations, blown head gaskets. Initially, GM denied it was a problem, but after being sued by a consumer group, GM relented and included overheating and blown head gaskets as a warranted item. GM issued a warranty for this after the fact for injectors, which now have 7 year/200,000 mile coverage.

The following trucks use the LB7:

  • Chevrolet Kodiak/GMC Topkick
  • Chevrolet Silverado/GMC Sierra HD

Specifications:

  • Engine type: 6,599 cc
  • (402.7 cu in) V8 turbo
  • Bore x Stroke: 4.06 in (103 mm) x 3.90 in (99 mm)
  • Block / Head: Iron / aluminum
  • Aspiration: Turbocharged & Intercooled
  • Valvetrain: OHV 4-V
  • Compression: 17.5:1
  • Injection: Direct; Robert Bosch GmbH high-pressure common-rail
  • Power / Torque:2001 235 hp @ 2,700 rpm 500 lb-ft @ 1,600 rpm LB7 introduced 2002 235 hp @ 2,700 rpm 500 lb-ft @ 1,600 rpm 2003 235 hp @ 2,700 rpm

500 lb-ft @ 1,600 rpm 2004 LB7: 300 hp @ 3,100 rpm LLY: 310 hp @ 3,000 rpm LB7: 520 lb-ft @ 1,800 rpm LLY: 520 lb-ft @ 1,600 rpm The LLY was introduced in 2004 and replaced the LB7 completely mid-year

The LLY (internally called the 8GF1) (engine code “2”) is a 6,599 cc (402.7 cu in) turbocharged engine which debuted in mid-2004 and continued until the end of 2005. It is a 32-valve design with high-pressure common-rail direct injection and aluminum cylinder heads. The LLY was GM’s first attempt to implement emissions requirements on their diesel trucks. To meet this goal they turned to a newly developed Garrett turbocharger with a variable geometry vane system and they installed an Exhaust Gas Recirculation valve or (EGR Valve). Learning from problems with injectors in the previous LB7 GM changed the valve covers to allow access to the injectors without having to remove the valve covers, saving significant labor costs if injector replacement became necessary.

The following trucks used the LLY engine:

  • 2006 Hummer H1 Alpha
  • Chevrolet Silverado/GMC Sierra HD

Specifications:

  • Engine type: 6,599 cc
  • (402.7 cu in) V8 turbo
  • Bore x Stroke: 4.06 in (103 mm) x 3.90 in (99 mm)
  • Block / Head: Cast gray iron / Cast aluminum
  • Aspiration: Turbocharged & Intercooled
  • Valvetrain: OHV 4-v
  • Compression: 17.5:1
  • Injection: Bosch High-Pressure Common-rail
  • Power / Torque: 305 bhp (227 kW) @3000 rpm / 605 lb·ft (820 N·m) @1600 rpm
  • Head casting is 8gf1
  • Block casting is #22351021213
  • The LMM (engine code “6”) debuted part way through 2007 and ended production with the start of the 2011 calendar year and is mated to the 6-speed Allison transmission. The LMM was the only Duramax offered for model years 2008-2010.

    Specifications:

    • Engine type: 6,599 cc (402.7 cu in) V8 turbo
    • Bore x Stroke: 4.06 in (103 mm) x 3.90 in (99 mm)
    • Block / Head: Cast gray iron / Cast aluminum
    • Aspiration: Turbocharged & Intercooled
    • Valvetrain: OHV 4-V
    • Compression: 16.8:1
    • Injection: Bosch High-Pressure Common Rail with CP3.3 Injection Pump
    • Power / Torque: 365 bhp (272 kW) @3200 rpm / 660 lb·ft (895 N·m) @1600 rpm

    Code Years Power@rpm Torque@rpm Redline (rpm)

    • LML (Chevrolet Silverado HD, GMC Sierra HD) 2011–present 397 bhp (296 kW) @3000 765 lb·ft (1,037 N·m) @1600 3450
    • LMM (Chevrolet Silverado HD, GMC Sierra HD) 2007–2010 365 bhp (272 kW) @3200 660 lb·ft (895 N·m) @1600 3450
    • LMM (Chevrolet Kodiak Medium Duty (LYE option), GMC TopKick Medium Duty (LYE option)) 2007–2010 330 bhp (250 kW) @3000 620 lb·ft (841 N·m) @1600 3250
    • LMM (Chevrolet Kodiak Medium Duty (LRX option), GMC TopKick Medium Duty (LRX option)) 2007–2010 300 bhp (220 kW) @3000 520 lb·ft (705 N·m) @1600 3250
    • LMM (Chevrolet Express, GMC Savana) 2007–2010 250 bhp (190 kW) @3200 460 lb·ft (624 N·m) @1600 3450
    • LMM (Chevrolet Express, GMC Savana) 2011-2014 260 bhp (190 kW) @3100 525 lb·ft (712 N·m) @1600 3450

    Emission controls:

    • Additional combustion control, including an even more efficient variable-geometry turbocharging system, cooled (enhanced) exhaust gas recirculation (EGR) and closed crankcase ventilation to reduce nitrogen oxides (NOx)
    • Additional exhaust control, including oxidizing catalyst and new diesel particulate filter (DPF) to reduce soot and particulate matter
    • Increased-capacity cooling system
    • New engine control software
    • Use of low-ash engine oil (CJ-4)

    Applications:

    • 2007- Chevrolet Silverado HD
    • 2007- GMC Sierra HD
    • Chevrolet Kodiak
    • GMC Topkick
    • Chevrolet Express/GMC Savanna

    The 6.6L RPO LML (VIN code “8”) is the 2011–2016 version of the Isuzu/GM Duramax V8 diesel engine. It is a further advanced version of the LMM engine with the majority of the changes addressing a required drastic reduction in engine emissions. Some mechanical aspects of the engine, such as piston oil flow design for improved temperature control and oil pump design, were also improved to enhance durability even further.

    The LML engine was significantly updated for 2011 to provide improved exhaust emissions that comply with the new federal emission standards for diesel engines, provide better engine rigidity and further noise reduction. New 29,000 PSI piezo injectors, a complete fuel system-hardening to tolerate up to 20% biodiesel mixtures and urea injection (to reduce nitrogen oxides) with a 5.3 gallon urea tank are updating the fuel and emissions systems. This engine has a fuel injector in the exhaust tract, to allow raw fuel injection during the particulate filter recycling routine. The RPO LML engine is rated at 397 horsepower (296 kW) at 3000 rpm and 765 lb·ft (1,037 N·m) of torque at 1600 rpm.