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Chevrolet Impala

Two very different cars share the badge, and knowing which one is in front of you decides almost everything. The W-body cars to 2013 are transverse V6 front-drive saloons — the 3.8 Series II and III are the ones most often met, and the upper intake manifold gasket is their signature failure, leaking coolant internally and producing misfire and lean codes on an engine that compresses perfectly. The 2014-on car moves to Epsilon II with the 2.5 four and the 3.6 direct-injection V6, whose faults are the opposite kind: timing chain stretch and carbon on the intake valves, not gaskets. Both eras use Passlock or immobiliser theft deterrent, which is a common cause of a no-start that reads as fuel or ignition and is neither.

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Chevrolet Impala, front view
SsmIntrigue · CC BY-SA 4.0 (external)

Generations

  • Eighth generation (W-body) 2000–2005

    Three pushrod V6s and nothing else: the 3.4 LA1, the 3.8 L36 and, on the 2004 and 2005 SS, the supercharged L67. The 3.8's upper intake manifold gasket leaks coolant internally and is behind most of the misfire and lean codes this car sets.

    Body styles
    Sedan
    Platform
    GM W-body
    Engines
    • 3.4 V6 — LA1 · petrol · 134 kW (180 hp) · 278 Nm (205 lb-ft)
    • 3.8 V6 — L36 · petrol · 312 Nm (230 lb-ft) · Series II
    • 3.8 supercharged V6 — L67 · petrol · 179 kW (240 hp) · 380 Nm (280 lb-ft) · SS, 2004-2005
    Transmissions
    4-speed 4T65-E automatic · 4-speed 4T65E-HD automatic
    Drivetrain
    Front-wheel drive
  • Ninth generation (W-body) 2006–2016

    Same platform, an entirely new engine range: the High Value 3.5 and 3.9 with active fuel management on some, the LS4 5.3 V8 in the 2006-2009 SS, and from 2012 a single direct-injection 3.6. The 3.5 and 3.9 are E85-capable, so a fuel-trim reading has to know what is in the tank. Sold on to fleets and police as the Impala Limited until 2016, alongside its own replacement.

    Body styles
    Sedan
    Platform
    GM W-body
    Engines
    • 3.5 V6 — LZ4 · petrol · 157 kW (211 hp) · 290 Nm (214 lb-ft) · LZE on the E85 cars
    • 3.9 V6 — petrol · LZ9, active fuel management on some
    • 3.9 V6 — LZ8 · petrol · 325 Nm (240 lb-ft)
    • 5.3 V8 — LS4 · petrol · 226 kW (303 hp) · 438 Nm (323 lb-ft) · SS only, 2006-2009
    • 3.6 V6 — LFX · petrol · 224 kW (300 hp) · 355 Nm (262 lb-ft) · from 2012
    Transmissions
    4-speed 4T65-E automatic · 4-speed 4T65E-HD automatic · 6-speed 6T70 automatic
    Drivetrain
    Front-wheel drive
  • Tenth generation (Epsilon II) 2014–2020

    Epsilon II with direct injection; chain stretch and intake-valve carbon replace the gasket faults of the W-body era.

    Body styles
    Sedan
    Platform
    GM Epsilon II
    Engines
    • 2.5 four-cylinder — LKW · petrol · 146–147 kW (196–197 hp) · 252–259 Nm (186–191 lb-ft) · LKW and LCV
    • 2.5 four-cylinder eAssist — mild hybrid
    • 3.6 V6 — LFX · petrol · 224–227 kW (300–305 hp) · 355–358 Nm (262–264 lb-ft) · LFX and LGX
    • 3.6 V6 bi-fuel — CNG bi-fuel
    • 2.4 — petrol
    Transmissions
    6-speed 6T45 Automatic · 6-speed 6T70 automatic · 6-speed 6T40 automatic
    Drivetrain
    Front-wheel drive

Service information

Information, not instruction

CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.

Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.

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