What are the symptoms of a faulty exhaust valve in an Audi A6?

[MicahLynn]

A faulty exhaust valve in an Audi A6 can cause a large amount of white smoke to emit from the exhaust pipe, along with engine shaking, unstable idling, and other issues. The function of the exhaust valve: The exhaust valve, also known as an oil separator or pressure control valve, is installed between the compressor outlet and the condenser inlet. Through separation, it improves the heat transfer efficiency in the condenser and evaporator. How the exhaust valve works: High-pressure gas (consisting of gaseous working fluid and lubricating oil) from the compressor enters the exhaust valve and flows through the guide vanes in a spiral motion. Centrifugal force and gravity separate the lubricating oil from the working fluid gas, causing the oil to flow along the inner wall of the cylinder. The working fluid gas is then directed out of the exhaust valve through a central pipe with multiple baffles. The separated lubricating oil collects at the bottom of the oil separator and can be periodically drained or automatically returned to the compressor's crankcase via a float valve.