The Top Repair Shop in Humble for Your BMW’s PCV Valve Failures

Posted on in BMW Repair

White BMW E92 M3 Car

BMW’s, just like any other car, can have a PCV (Positive Crankcase Ventilation) valve issue. When caught early, this is a minor problem. In fact, a failing PCV valve can be easily detected during a routine check. In this article, we will discuss the significance of a PCV valve, some signs that it is failing, and what you can do about it.

What is a PCV Valve, and What Does It Do?

The PCV valve is a spring-loaded, one-way valve that is usually located on top of the car’s engine and connected to the intake manifold with a hose. Its job is to help redirect and recycle the fumes created during combustion away from the crankcase. It reroutes these gasses through the air intake so that it can be burned again in the engine’s combustion chamber. A functioning PCV valve only allows these gasses to exit the crankcase but never enter it.

Why is the PCV Valve so Important?

The crankcase holds the motor oil. When the air-fuel mixture is burned in the engine, it creates waste gases, known as blow-by gasses, which often contain unburned fuel. If these gasses pass into the crankcase, they mix with the oil and form sludge, which can clog up the system or cause corrosion. Pressure can also build up in the crankcase due to this, which may result in oil leaks. Basically, the PCV valve protects the engine and the crankcase from these harmful gasses. A faulty PCV valve can create havoc in the engine and can also release dangerous exhaust gasses into the environment.

Signs That The PCV Valve is Not Working

If your PCV valve is dysfunctional, you will very quickly begin to notice some serious problems. Please do not ignore these, as it could lead to severe issues with your Bimmer’s engine. Remember, similar symptoms can manifest for various other reasons. The only way to know for sure is to have a professional mechanic inspect your BMW.

  • Oil Leaks: If pressure builds up in the crankcase, it can cause oil to ooze out through the seals and gaskets. You may see engine oil around the crankcase and on different engine parts where it shouldn’t be, even on the MAF (mass air flow) sensor or the spark plugs.
  • Rough Idling: If your car lunges or vibrates while idling, it could be because the PCV valve is stuck.
  • Stalling: Your Beamer may want to surge or stall when you’re trying to start it. A stuck PCV valve impedes the correct amount of air-fuel mixture to pass through the intake manifold and will disrupt performance, including failure to start.
  • Increased Oil Consumption: A problematic PCV valve can allow extra oil to flow into the intake manifold.
  • Reduced Fuel Efficiency: Bad gas mileage is often an indication that you may have a faulty PCV valve.
  • Increased Emissions and Black Smoke: If you notice increased emissions, especially black smoke, coming out of your BMW’s exhaust pipe, you may want to have the PCV valve checked out.
  • Engine Misfiring: This is a common side-effect of a malfunctioning PCV valve, as the engine is running too lean or too rich. There is either too much air or too little air in the air-fuel mixture.
  • Sludge Build-Up: If you can actually see sludge in your engine oil, that is definitely due to a poorly performing PCV valve.
  • Erratic RPMs: Because of the incorrect air-to-fuel mixture, your Beemer may run rich or lean, causing sporadic acceleration. This may register on your tachometer as a fluctuating gauge, showing wavering RPMs (Revolutions per Minute).
  • Check Engine Light (CIL): This catch-all warning is there to tell you that something is wrong with the engine. It is critical that you pay attention to this. An OBDII-scanner (On-Board Diagnostic) scanner can diagnose and reveal what the problem is.

What Happens If You Drive With a Malfunctioning PCV Valve?

The short answer is that you should not BMW PCV Valve Check drive your car with a faulty PCV valve. If you notice any of the above issues, promptly take your BMW to a professional garage. Just the sludge, which is a thick gel and consists of partially burned fuel, dirt, grime, and metal fragments, could cause permanent engine damage. Only an engine rebuild will fix that problem! We recommend you have your BMW on a regular maintenance schedule.

At Motorwerks Auto Group, our highly trained mechanics are specialists in European luxury automobiles. Give us a call or make an appointment to stop by. We are in Humble, Texas.

* White BMW E92 M3 Car image credit goes to: Brandon Woyshnis.

Written by Travis Thompson