Volkswagen Golf/Jetta/Cabriole 1990-1999

Fuel/Water Separator (Diesel Engines)


Draining Water

Although diesel fuel and water do not readily mix, fuel does tend to entrap moisture from the air each time it is moved from one container to another. Eventually every diesel fuel system collects enough water to become a potential hazard. Fortunately, when it's allowed to settle out, the water will always drop to the bottom of the tank or filter housing. Some diesel fuel filters are equipped with a water drain; a bolt or petcock at the bottom of the housing.

Most 1990-92 diesel engine-equipped vehicles are equipped with a water separator, located in front of the fuel tank under the right side of the vehicle. The water seperator's purpose is to allow water to settle from the fuel right at the tank and to alert the driver when draining is required. When the water level in the separator reaches a certain point, a sensor turns on the glow plug indicator light on the dashboard, causing it to blink continuously. With the introduction of the A3 platform, the water separator was eliminated, and removing water from the fuel system is accomplished with a drain screw on the bottom of the fuel filter.

At The Water Separator

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Fig. The water separator includes a sensor that flashes the glow plug light when draining is required

  1. Raise and safely support the vehicle. Remove the fuel filler cap.
  3. At the separator, connect a hose from the separator drain to a catch pan.
  5. Open the drain valve (3 turns) and drain the separator until a steady stream of fuel flows from the separator, then close the valve. Don't forget to install the filler cap.

At The Filter

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