2005 Audi S4 Fuel Filter Replacement Cost

Fuel filters are typically mounted to the undercarriage, on the main fuel line after the fuel pump. The filter traps particulates as the fuel flows through it. This keeps contaminants away from sensitive fuel injectors, rails, and fuel pressure regulators, preventing more expensive damage.

When the fuel filter begins to clog, the engine suffers from fuel starvation. This will cause a significant reduction in power and may also cause a misfire. These conditions may be intermittent, or constant and worsen over time. As the issue progresses, the engine may being to stall immediately after starting, fail to start, hesitate under throttle, or stall at particular angles on hills.

If a driveability problem such as a clogged fuel filter exists, driving is not advised. A vehicle that accelerates unpredictably, or stalls every few moments is a hazard to you and those around you, increasing the possibility of the engine shutting down on the highway. The vehicle may also be impossible to drive, since the fuel cannot reach the engine.

Fuel filters are a maintenance item, your owner's manual will have the manufacturer's recommended schedule for replacement. We typically see fuel filters replaced every 40,000 - 80,000 miles. Fuel filters should be replaced according to the service schedule, not just when a related problem occurs.

Changing the fuel filter normally does not require a diagnosis. They are most often replaced as scheduled maintenance, or as part of a repair necessitating early replacement of the fuel filter. If the fuel system is being diagnosed, the fuel filter may be replaced as a step in the diagnosis. If the fuel filter has been run past the replacement interval, or if it was noted that the fuel tank had contaminants in it, the filter will immediately be suspected of failure in the case of any fueling issue.

For an in-line filter, there are two lines on either end of the filter that need to be released. Some GM vehicles require special tools to release the lines, while some European vehicles will require at least one line wrench to break the metal line fittings loose. The sealing washers will need to be replaced as well to prevent leaks from the new filter. If any debris or dirt are noted from the filter inlet line, the fuel tank will be inspected for corrosion and contaminants.

We recommend using OEM quality or better when selecting a new fuel filter. Inferior fuel filters will allow contaminants pass through, and reach the fuel system more often.

Some older vehicles may locate the fuel filter on the firewall. When servicing this placement of filter, it is important to keep rags handy to catch fuel spilling from the filter. Removing a dripping fuel filter in a hot engine bay is a potential fire hazard.

Depending on location of the filter, fuel filter replacement can be done at home by an intermediate DIYer. Most require lifting and safely supporting the vehicle in order to access the filter, and some will require removal of under-body paneling. Fuel filters are more easily replaced with a set of fuel line release tools. These are available from many auto parts stores, or online. They allow the technician, or DIYer to remove the fuel lines without breaking any of the fragile plastic clips. Care should be taken to catch fuel that falls from the filter or line during this service. Any time the fuel system is opened there is risk of fire.