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2008 Chevrolet Express 3500

Reliability tier: verified - see /disclosure/

Engine: 6.6L Duramax LMM (van tune) (Duramax, 6.6L)

The van-tune LMM: 250 hp / 460 lb-ft (TheDieselPage, MY2007 van intro article) - a heavy derate of the 365/660 truck LMM, paired with the 4L85-E (the uprated 4L80-E-family unit used behind the 2006-2010 Duramax vans - not the base 4L80-E). MID-YEAR SWITCH: MY2007 vans overlap LLY (early builds) and LMM - a MY2007 van diesel resolves by build date (same rule as the truck mid-year switches). The LLY vans (MY2006-2007) are documented but not covered here yet (the platform's LLY generation is truck-calendared 2004-2005).

Applicable failure modes (5)

• LMM DPF-era service (regeneration / ash service)
• EGR cooler clogging / failure (LB7-LMM)
• CP3 pump / fuel system contamination
• Head gasket failures (higher mileage / load)
• VGT turbo vane carbon / actuator wear (LLY+)

Applicable parts (9)

• Duramax LBZ/LMM CP3 Injection Pump (Reman OEM)
• duramax-lb7-lmm: dpf (honest catalog gap)
• Duramax LMM DPF Differential Pressure Sensor (OEM)
• Duramax LBZ/LMM Glow Plug (OEM)
• Duramax LBZ/LMM Cylinder Head Gasket Kit, W/O Head Gaskets (OEM)
• Duramax LMM Fuel Injector (Reman OEM)
• Duramax LMM Turbocharger Assembly (OEM)
• Duramax LBZ/LMM Turbo Vane Position Sensor (OEM)
• Duramax LBZ/LMM Water Pump (OEM)

Platform recipes (6)

• CP3 and fuel-system contamination service (fm-dmx-fuel-system-health): the Bosch CP3 is fed by the OEM filter setup, and water/debris are the standing threats
• LMM DPF-era service (fm-dmx-dpf-era-service): the LMM (from mid-2007) is the first DPF Duramax
• EGR cooler service (fm-dmx-egr-cooler): the Duramax has carried cooled EGR since the LB7 (catalog-verified 97288793 for 2002-2004) and the coolers clog with carbon and eventually leak - the LLY-era heat reputation makes cooler health the first check on heat complaints
• Head-gasket replacement path (fm-dmx-head-gaskets): stock gaskets age and elevated cylinder pressures finish them
• Repair path for the LB7's defining failure (fm-dmx-lb7-injectors): hard starts, white smoke, fuel dilution on 2001-early-2004 trucks
• VGT turbo service path (fm-dmx-vgt-turbo): boost flutter, slow spool, smoke under load