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Maintenance/Replacement of the Breather Unit

Model: Audi A8 - Years: 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
Part: Engine

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The engine is a system of moving mechanical parts, and internal pressures are generated due to its dynamics. These pressures must be reduced, and the only solution is to create a vent to the outside.

Unfortunately, the fumes from the engine are carcinogenic because they contain combustion residues and oil molecules. To reduce pollution, these fumes are recirculated to the engine intake, between the air filter and the compressor, to burn all the harmful molecules.

To prevent damage to the compressor impeller, filters and separators have been installed in the recirculation circuit to avoid oil droplets directly impacting the compressor blades. If maintenance of these filters, called breather units, is not performed, the passage partially clogs, creating the negative effect of increased pressure in the oil pan. Replacing the breather unit is extremely simple: just unscrew the mounting clamps.


Updated on 14 February 2026 by ScegliAuto


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