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How to Replace the Thermostat Valve on VW Golf IV

Model: Volkswagen Golf Golf IV, MK 4, Golf 4 - Years 1997-2003
Part: Thermostat

If you experience issues with the coolant temperature rising, one possible cause is a malfunctioning thermostat valve. Rust formation in the cooling system can cause the thermostat valve to become stuck. To replace this valve, start by draining the coolant through the radiator hose (ensure the engine is cold) and locate the valve seat just behind the alternator. Then, unscrew the fastening bolts of the flange housing the valve, remove the old valve, and insert the new one, applying a new O-ring and gasket to the flange before refitting it. Finally, refill the system with the appropriate coolant.

Updated on 19 February 2026 by ScegliAuto

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