General information (Audi A6 C5)

The fuel system includes the fuel tank, fuel lines, fuel filter, fuel pump and injection device (separate chapter).

The plastic fuel tank is located under the vehicle's underbody behind the rear axle. The amount of fuel in the tank is displayed by a fuel gauge located in the instrument cluster. The fuel tank is ventilated by a closed ventilation system. Harmful gasoline vapors from the fuel tank ventilation are captured by an activated carbon accumulator.

Economy driving mode

The way you drive your car has a significant impact on fuel consumption.

• After starting the engine, start driving immediately, even in freezing temperatures.
• If stops are expected to last more than 40 seconds, turn off the engine.
• Drive in the highest possible gear.
• Try to maintain a constant speed on the longest possible sections of the road, avoid high speeds. When driving, be prudent, and do not brake unnecessarily.
• Do not carry unnecessary additional cargo in your vehicle; remove any attachments, such as roof racks, from your vehicle as soon as possible.
• Check tire pressure regularly, do not operate the vehicle with low tire pressure.

Safety rules when working on the fuel system

When working on the fuel system, observe the following safety and hygiene rules:

Safety instructions

• When working on the fuel system, do not use open flames, electric welding or tools that may generate sparks. Make sure that a charged fire extinguisher is in the immediate vicinity of the work area.
• Work on the fuel system must be carried out in a well-ventilated area, for which you can open all windows and doors to create a draft.
• The fuel system is under pressure. When disconnecting system components, fuel may splash out, so use goggles to protect your eyes from fuel getting into them. If fuel gets on your skin, rinse the area with plenty of water. Collect any leaking fuel with a rag.

Hoses are secured to pipelines using band clamps or clamping brackets. Clamping brackets are replaced with band clamps during repairs. The use of clamping or screw clamps is not permitted. Special pliers, such as HAZET 798-5, are used to install band clamps.

• Before disconnecting, thoroughly clean the connection points and adjacent areas.
• Place the removed parts on a clean surface and cover them with foil or paper. Do not use fibrous rags.
• Close or plug open connections if repairs are to be made over a period of time.
• Install only clean parts. Remove spare parts from their packaging immediately before installing them. Do not use parts that are not packaged (for example, in toolboxes, etc.).
• If possible, do not work with compressed air when the fuel system is open. Try not to move the car.
• Do not use silicone-containing sealants. The residues of silicone components sucked in by the engine do not burn in the engine and damage the lambda sensor.