Upper Intake Manifold with Gasket for Chevrolet Impala (2000-2005) 3.8L

Direct-Replacement Upper Intake Manifold Kit for 2000-2005 Chevrolet Impala (W-Body)

What it Does: The upper intake manifold kit replaces the degraded factory intake plenum on the 2000-2005 Impala to eliminate vacuum leaks and prevent catastrophic internal coolant migration.

The Stock Chevrolet Impala EGR Bore Degradation

The factory composite nylon upper plenum on the GM 3800 Series II L36 engine suffers from a documented thermal failure point adjacent to the exhaust gas recirculation (EGR) passage. Continuous heat cycling from the internal metallic EGR stovepipe softens and erodes the surrounding composite material. Over time, this structural fatigue compromises the adjoining coolant bypass passages, allowing pressurized engine coolant to seep directly into the intake runners, lower intake valley, and cylinders, risking misfires, catalytic converter contamination, or hydraulic lock.

The Engineering Solution

This replacement upper plenum is molded from high-grade, heat-stabilized thermoplastic engineered to resist prolonged thermal soak from exhaust gas recirculation. Calibrated runner geometry matches factory volumetric efficiency and manifold absolute pressure (MAP) parameters without requiring ECM recalibration. The kit includes an upgraded port gasket carrier featuring molded elastomeric perimeter seals, replacement throttle body studs, fuel pressure regulator hardware, and precision O-rings to completely restore structural vacuum sealing across the entire W-Body induction tract.

What's Included

• 1 Upper Intake Manifold (plastic plenum)
• 1 Upper Intake Manifold Gasket with port seals
• Fuel pressure regulator spring
• Throttle body studs
• O-rings and installation fittings

Technical Specifications

Compatibility

• 2000-2005 Chevrolet Impala 3.8L V6 Gas Naturally Aspirated (L36)

Frequently Asked Questions & Fitment Warnings

Does this fit the W-Body Impala?

Yes, this is a direct fit for the 2000-2005 Chevrolet Impala equipped with the 3.8L L36 engine. This kit does not fit 3.4L V6 base models or supercharged 3.8L L67 SS models.

Do the intake manifold bolts require a specific torque sequence?

Yes, always torque plenum fasteners in the factory-specified spiral sequence from the center outward to 89 lb-in to prevent warpage and port seal pinch.

The Chevrolet Reliability Standard

Engineered to deliver long-haul reliability, this replacement plenum restores factory throttle response, vacuum stability, and leak-free performance for your daily-driven GM 3800 Series II powertrain.