Inlet Manifold Base Gasket - Waterboxer Engines With Fuel Injection (4mm Thick)

This replacement inlet manifold gasket fits between the inlet manifold and the cylinder head on Volkswagen Type 25 / T3 buses equipped with fuel-injected 1900cc and 2100cc Waterboxer engines. Manufactured from thick Bakelite insulating material, this gasket is designed to provide both a reliable airtight seal and thermal insulation between the manifold and cylinder head.

On fuel-injected Waterboxer engines, maintaining an airtight seal at the manifold is critical for correct air–fuel mixture and stable engine running. The insulating properties of this gasket help reduce heat transfer from the cylinder head into the intake manifold, keeping intake air temperatures lower and improving overall engine efficiency. Over time, original gaskets can become brittle, warped, or crushed, leading to vacuum leaks, rough idle, hesitation, and lean running.

This gasket is manufactured to the correct 4mm thickness and original specification, making it ideal for engine rebuilds, intake system servicing, or curing vacuum leak issues.

How it works

The gasket seals the joint between the inlet manifold and the cylinder head, preventing unmetered air from entering the engine. Its insulating material also helps protect the intake charge from excess heat, contributing to smoother running and consistent fuel injection performance.

Specifications

• Material: Bakelite insulating gasket

• Thickness: 4mm

• Position: Inlet manifold to cylinder head

• Quantity: Sold individually (2 required per engine)

Fitment & installation notes

• Suitable for fuel-injected Waterboxer engines only

• Always replace gaskets when removing the inlet manifold

• Recommended to check manifold studs, nuts, and sealing faces during installation

Engine compatibility

1.9 Waterboxer (Fuel Injection):

• DH

• GW

2.1 Waterboxer (Fuel Injection):

• DJ

• MV

• SR

• SS