What are the symptoms of a faulty exhaust valve in an Audi Q5?
2 Answers
If there is a large amount of white smoke coming from the exhaust pipe, accompanied by engine shaking, unstable idle speed, etc., it is highly likely that the car's exhaust valve is damaged. The exhaust valve, also known as the oil separator or pressure control valve, is installed between the compressor outlet and the condenser inlet. It improves heat transfer efficiency in the condenser and evaporator through separation. Below is additional information: 1. How the exhaust valve works: The high-pressure gas (gaseous working fluid and lubricating oil) from the compressor enters the exhaust valve and passes through the guide vanes, flowing in a spiral pattern. Centrifugal force and gravity separate the lubricating oil from the working fluid gas, which then flows along the inner wall of the cylinder. The working fluid gas is discharged from the exhaust valve through a multi-baffle tube in the center. The separated lubricating oil accumulates at the bottom of the oil separator and can be periodically drained or automatically returned to the compressor's crankcase via a float valve. 2. Causes a large amount of blue smoke: This indicates a more severe case of oil burning. Therefore, when encountering the above symptoms, car owners must promptly inspect and repair the issue.
When I was driving my Audi Q5, the faulty PCV valve almost caused me embarrassment, and the car had quite a few issues. The most noticeable was severe engine shaking at idle, like it had too much to drink, vibrating the steering wheel. The engine warning light on the dashboard kept flashing, urging me to get it checked. Acceleration felt particularly weak, with no response even when flooring the gas pedal, and fuel consumption skyrocketed—previously, a full tank could go 400 km, but after the fault, it barely made 300 km. Even more annoying was the car coughing and failing to start or suddenly stalling while driving, which was truly frightening. Later, when I took it for repairs, the mechanic said the clogged PCV valve caused exhaust gas recirculation issues, overburdening the engine, and could potentially damage other components over time. The lesson I learned: fix problems early to avoid bigger troubles later.
