G3 Water Flange - 1.9 Diesel

This high-quality coolant flange with base seal is a direct replacement for the factory-fitted unit used on a wide range of Volkswagen 1.9 diesel engines. The coolant flange is mounted on the cylinder head and acts as a junction point for coolant flow, connecting hoses, temperature senders and various engine cooling channels. Over time, the original plastic flanges are prone to cracking, warping or leaking due to continual heat cycling, vibration and age. A leaking flange can lead to coolant loss, overheating and poor heater performance—common issues on older 1.9 TDI, TD and SDI engines.

Manufactured from durable heat-resistant plastic, this replacement flange matches the original dimensions and port layout, ensuring a precise fit with all factory hoses and sensors. The included base gasket seal restores a tight, leak-free connection between the flange and the cylinder head. Installation is straightforward and typically carried out during coolant system servicing, head gasket repairs or when diagnosing unexplained coolant loss.

When replacing the flange, it is advisable to inspect the connected hoses, temperature sender O-rings and the expansion tank for signs of age-related degradation. Many owners choose to renew the thermostat at the same time to maintain efficient cooling system performance.

Engine Codes Covered

• 1Z – 1.9 TDI

• AEY – 1.9 SDI

• AFN – 1.9 TDI

• AHU – 1.9 TDI

• ALE – 1.9 TDI

• AKW – 1.7 SDI

Confirmed Vehicle Fitment

• VW Golf Mk3 – 1992–1998

• VW Golf Mk3 Cabrio – 1994–2002

• VW Polo Mk3 (6N) – 1996–2000

• VW Vento – 1992–1998

A perfect replacement part for restoring a reliable, leak-free coolant system on classic VW diesel engines.