VW 2.0 TSI PCV Valve Failure Symptoms

Volkswagen’s 2.0 TSI (Turbocharged Stratified Injection) engine, which is now in its fourth generation, has been in production since the late 2000s. A chain-driven, direct injection, turbocharged four-cylinder engine, the 2.0 TSI offers stellar performance and fuel economy. It has powered everything from the VW Passat, Tiguan, and GTI, to the Audi TT, A4, A6, and Porsche Macan. Safe to say it’s a workhorse engine for the Volkswagen Group. Generally, it’s been reliable through the first three generations (the fourth generation has not been out for long). 

Depending on the year, the TSI engine has some notable issues. These problems have ranged from carbon buildup to turbocharger failure. One issue that has persisted across the generations is PCV valve failure. Read on to learn more about some of the most common symptoms of PCV valve failure on the 2.0 TSI!

What is PCV?

PCV stands for Positive Crankcase Ventilation. Its job is to release unwanted gasses from the crankcase and route them back through the engine intake. The gasses then combust with the air and fuel mixture, passing through the exhaust system. 

The seals in your engine do a pretty good job of keeping things separate. However, some gasses make their way from the combustion chamber past the piston rings into the crankcase (the crankcase is part of the engine that holds the oil and moving parts like the pistons and crankshaft). This phenomenon is known as blow-by. 

The PCV system reduces emissions and prevents engine seals from being blown out by excess pressure in the crankcase. PCV also prevents oil sludge from developing, which can happen when the blow-by gasses mix with oil. 

What is a PCV Valve?

The PCV valve is an essential part of the whole system. The PCV valve only allows gas to flow one way. When crankcase pressure builds, the valve directs gasses out of the engine to the intake. On the 2.0 TSI, the PCV valve sits on top of the valve cover. It is easily identifiable by the round, black, puck-shaped diaphragm, although the entire valve is much larger.

Symptoms of PCV Valve Failure on the 2.0 TSI

When the PCV valve fails, it can cause some strange symptoms.

Screeching Sound

One of the most blatant symptoms of a failing PCV valve is a loud screeching noise from the engine bay. This sound can be incredibly loud and is a sign you should bring your vehicle to a professional. 

Check Engine Light

A failed PCV valve can cause excess air to enter the engine, which triggers a check engine light. The code P0171 will indicate the engine is running lean, which means there is too much air and insufficient fuel entering the motor. Another code associated with PCV failure is P0507, which indicates the idle RPM is too high.

Idle Problems

You may notice irregular, rough, or choppy idle when the PCV valve is failing. As stated above, the idle RPM may also be higher than normal. More noise and shaking make this symptom very noticeable from the driver’s seat. 

Oil Leaks / Rear Main Seal Failure

Oil leaks caused by a bad PCV valve can range in severity from minor to catastrophic. Oil can leak from the seal where the valve meets the metal valve cover. You might notice oil seeping out from around the valve when you pop the hood of your vehicle. 

Another issue that can arise as a result of a faulty PCV valve is a leaking rear main seal. The rear main seal sits on the end of the motor where the crankshaft connects to the transmission. Fluctuations in crankcase pressure cause the seal to fail. Severe rear main seal leaks can cause major engine damage from oil starvation. 

Misfires

Another very common symptom of PCV failure is engine misfires. The engine computer can only accommodate so much excess air entering the engine. As a result, a severe leak can lead to misfires. Misfires can cause a blinking check engine light and should be addressed as soon as possible to prevent damage to the catalytic converter. 

What Causes PCV Valve Failure?

There are two common failure points on the 2.0 TSI PCV valve. The rubber diaphragm inside the circular valve on top of the PCV valve can tear, and the orange check valve on the underside of the unit can become stuck. 

PCV Valve Replacement at Becker Service Center

If your VW or Audi is showing signs of PCV valve failure, make sure to get it looked at by a professional right away! For those in the Naperville area, stop in or schedule an appointment here at Becker Service Center. Our expert technicians have experience servicing European vehicles and will get your 2.0 TSI running as it should. Call or schedule an appointment online today!