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GM 3.0L Duramax I6 (LM2/LZ0) platform

GM 3.0L Duramax LM2/LZ0 I6 (2020+)

2020-2026 · 3.0L · General Motors

42

vehicle configs

9

failure modes

20

parts

4

recipes

recalls + bulletins →

symptoms compared →

buyer's checklist →

EcoDiesel and 3.0 Power Stroke →

Failure modes

Coolant flow control valve failure (active thermal management)

DEF system faults: tank heater, pump/quality (speed-limited derate)

DPF regeneration and ash-loading faults

EGR system failures: valve, cooler, wiring (derate-prone)

Extended crank / long-crank no-start (air intrusion, check valve, cam wheel)

NOx sensor / SCR efficiency codes

LZ0 crankshaft thrust bearing failure (GM bulletin 25-NA-307)

Transmission control valve failure and rear-wheel lock-up (recall 24V-797)

Turbo and boost-path faults (coolant line, charge air)

Parts

3.0L Duramax Engine Coolant Flow Control Valve (GM 24001355) part-lm2-coolant-control-valve 3.0L Duramax DEF Controller (GM 85514348) part-lm2-def-controller DEF refill - fresh API-certified fluid (service item, all 3.0L Duramax) part-lm2-def-fluid-service 3.0L Duramax DEF Tank Assembly, pickups 2020-2022 (GM 86790695) part-lm2-def-tank-2020-2022 3.0L Duramax DEF Tank Assembly, pickups 2022-2024 (GM 87867197) part-lm2-def-tank-2022-2024 3.0L Duramax DEF Tank Assembly, SUVs 2021-2023 (GM 86772598) part-lm2-def-tank-suv DPF cleaning service (professional bake-and-blow, off-truck) part-lm2-dpf-cleaning-service 3.0L Duramax DPF Differential-Pressure Pipe (GM 55496942) part-lm2-dpf-pressure-pipe 3.0L Duramax EGR Cooler (GM 55513487) part-lm2-egr-cooler 3.0L Duramax EGR Valve, high-pressure circuit (GM 55510043) part-lm2-egr-valve-hp 3.0L Duramax EGR Valve, low-pressure circuit (GM 55510254) part-lm2-egr-valve-lp 3.0L Duramax EGR Valve, LZ0 high-pressure circuit 2023-2024 (GM 40009269) part-lm2-egr-valve-lz0 3.0L Duramax Fuel Filter / Water Separator Assembly (GM 13543066) part-lm2-fuel-filter 3.0L Duramax Fuel Filter Kit (GM 13539108) part-lm2-fuel-filter-kit 3.0L Duramax Drop-In Fuel System / Lift Pump (FASS, 2019-2026 GM 3.0 LM2/LZ0) part-lm2-lift-pump-fass 3.0L Duramax NOx Sensor, Position 1 (GM 24001898) part-lm2-nox-sensor-posn-1 3.0L Duramax NOx Sensor, Position 2 (GM 24001899) part-lm2-nox-sensor-posn-2 3.0L Duramax NOx Sensor, Position 3 (GM 24001900) part-lm2-nox-sensor-posn-3 3.0L Duramax Turbocharger (GM 40009138) part-lm2-turbo 3.0L Duramax Turbo Wastegate Actuator Kit (GM 12716475) part-lm2-turbo-actuator-kit

Recipes

Coolant flow control valve job for the 3.0L Duramax (mode fm-lm2-coolant-control-valve): high fan, fluctuating temp, P1098, 'Engine Power Reduced'

DEF tank-side service for the 3.0L Duramax (mode fm-lm2-def-system): the 'Exhaust Fluid System' warnings walk up a derate ladder to 5 mph

EGR cooler / valve job for the 3.0L Duramax (mode fm-lm2-egr-system): rarely named in NHTSA complaints (8 of 1,190) but forum-documented - recurring 'Service Emission System' with the 65-mph derate

Fuel filter service with a proper prime for the 3.0L Duramax (mode fm-lm2-long-crank): the #1 self-inflicted long-crank is air trapped after a filter change - seat the housing fully, cycle key-on and let the pump prime before cranking

From the blog

Buyer's guideGM 3.0L Duramax LM2/LZ0 I6

EcoDiesel vs 3.0 Power Stroke vs 3.0 Duramax: Which Used Half-Ton Diesel, and What to Check

October 18, 2026 · 16 min read

Reference for this engine

Oil, filters and coolant: 3.0 Duramax (LM2), 2022

from the owner's manual

Repair costs for this engine

4 failures priced in parts

Part number lookup

every OEM number we verified

Is this the engine in my truck?

the 8th character of the VIN

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