Upper Intake Manifold with Gasket for Pontiac Grand Prix (1997-2003) 3.8L

Reinforced Upper Intake Manifold Replacement for 1997-2003 Pontiac Grand Prix (W-Body)

What it Does: The Upper Intake Manifold with Gasket replaces the failure-prone factory plenum on the 1997-2003 Pontiac Grand Prix to eliminate unmetered vacuum leaks and prevent catastrophic internal coolant loss.

The Stock Pontiac Grand Prix EGR Burn-Through and Plenum Warpage

The factory composite upper plenum on the GM 3800 Series II engine suffers from a notorious structural vulnerability adjacent to the exhaust gas recirculation (EGR) passage. Continuous thermal cycling from hot exhaust gases causes the factory nylon to degrade, thin, and rupture around the internal stovepipe. Once breached, pressurized coolant bypasses the seal directly into the lower intake runners, causing rough idling, cylinder misfires, severe hydraulic lock risks, and bearing washout across the L36 engine assembly.

The Engineering Solution

Engineered from premium heat-stabilized composite polymer, this replacement upper plenum resists thermal fatigue and prevents localized burnout around the EGR port. Precision-engineered sealing grooves maintain uniform clamp load to prevent runner distortion under heat soak and continuous engine vacuum. Supplied with an upgraded port-matched perimeter gasket and essential mounting hardware, this manifold assembly restores factory intake manifold absolute pressure (MAP) readings, protects the combustion chambers, and secures long-term valvetrain reliability.

What's Included

• 1 Upper Intake Manifold (Reinforced Composite Plastic)
• 1 Upper Intake Manifold Gasket with Port Seals
• Fuel Pressure Regulator Spring
• Throttle Body Studs
• O-Rings and Assorted Fittings

Technical Specifications

Compatibility

• 1997-2003 Pontiac Grand Prix 3.8L V6 Gas Naturally Aspirated

Frequently Asked Questions & Fitment Warnings

Does this fit the W-Body Grand Prix?

Yes, this is a direct fit for the 1997-2003 Pontiac Grand Prix equipped with the naturally aspirated 3.8L L36 engine. Does not fit supercharged L67 models, which utilize a dedicated cast-aluminum intake manifold and Eaton M90 supercharger.

What is the recommended installation procedure for the manifold fasteners?

Install on a completely cold engine and torque all upper intake fasteners in the factory crisscross sequence to 89 in-lbs (10 Nm) to avoid uneven carrier stress and gasket pinching.

The Pontiac Performance Standard

Engineered to withstand the demanding thermal dynamics of GM's legendary 3800 V6 platform, this intake manifold restores vital structural integrity and factory airflow calibration, giving your performance sedan dependable sealing mile after mile.