Bilstein has issued technical guidance targeting coolant overheating and heating failure on VAG 1.4-litre TDi engines fitted across Audi, SEAT, Skoda, and Volkswagen models.
Vehicles experiencing the fault may display coolant temperature gauge readings exceeding 110°C, poor interior heater output, and logged cooling system ECU fault codes.
Engine overheating occurs when the OEM water pump’s ECU-controlled thermal management collar seizes. Alternatively, the internal plastic impeller can break up or detach from the drive shaft, stopping coolant circulation.
Technicians can diagnose flow restriction by checking the header tank return pipe:
- Testing procedure: Remove small pipe over coolant header tank filler neck with engine cool and idling
- Flow verification: Observe coolant flow while increasing engine speed; lack of increased flow indicates water pump failure
To prevent recurring failures, febi supplies part number 108778, a conventional design water pump that eliminates the problematic control collar mechanism.
When installing febi 108778, technicians must transfer the solenoid valve from the original pump onto the replacement unit to ensure engine management recognition and avoid fault logging. Following installation, workshops should vacuum bleed the cooling system before executing serial diagnostic tool bleed routines to purge trapped air.
Technical details and vehicle applications can be checked via partsfinder.bilsteingroup.com, with company details at www.bilsteingroup.com.