← Back
2023 Chevrolet Express 2500
Reliability tier: verified - see /disclosure/
Engine: 6.6L V8 Gas (L8T) (GM Gen V V8 Gas, 6.6L)
The Gen-V 6.6L L8T gas V8 in the vans (401 hp / 464 lb-ft, same rating as the HD trucks - the van did not derate it). Van intro MY2021 (replacing the L96; the vans skipped the truck's MY2020 L8T year). 6L90-E through MY2023, 8L90-E from MY2024 (the 2024 van transmission update).
Applicable failure modes (5)
- Intake-valve carbon buildup (direct injection, no port wash)
- Cooling system wear: water pump, hoses, thermostat (towing duty)
- Direct-injection high-pressure fuel pump / injector failures
- Ignition service wear: spark plugs and coils
- Valvetrain hardware failures: lifters, valves (no AFM - attribution guard)
Applicable parts (13)
- gm-hd-gas-l8t: oil-catch-can-kit (honest catalog gap)
- gm-hd-gas-l8t: coolant (service item)
- gm-hd-gas-l8t: cylinder-head (honest catalog gap)
- gm-hd-gas-l8t: fuel-filter (honest catalog gap)
- gm-hd-gas-l8t: hpfp (honest catalog gap)
- gm-hd-gas-l8t: ignition-coil (honest catalog gap)
- gm-hd-gas-l8t: injector (honest catalog gap)
- gm-hd-gas-l8t: intake-valve-cleaning-service (service item)
- gm-hd-gas-l8t: engine-long-block (honest catalog gap)
- 6.6L L8T Spark Plug (OEM)
- 6.6L L8T Spark Plug Wire (OEM)
- 6.6L L8T Thermostat Kit (OEM)
- 6.6L L8T Water Pump (OEM)
Platform recipes (3)
- Cooling inspection and wear-item service for the 6.6L L8T on a towing HD truck: pressure-test, weep hole, hoses, thermostat (mode fm-l8t-cooling-wear)
- L8T ignition service (mode fm-l8t-ignition): no L8T-specific defect exists - this is conventional Gen V truck hardware on service intervals, and the honest recipe is interval discipline
- Rough idle or hesitation on a high-mileage 6.6L L8T: direct injection leaves the intake valves unwashed - borescope before cleaning, and rule out ignition and injectors (same symptoms) (mode fm-l8t-carbon)