BMWs are one of the most admired vehicles on the road. They are high-performance cars that are comfortable to drive and reliable. Most issues that BMWs experience can be avoided if regular maintenance is performed; this includes crankcase ventilation valve failure.

What is the crankcase ventilation valve?

The crankcase ventilation valve is part of the PCV system, also known as the Positive Crankcase Ventilation system. The crankcase is located directly below the cylinders. The purpose of the PCV system is to remove gases from the crankcase. They are then sent to the intake manifold where they are burned.

Before the PCV system was created, unburned fuel was able to leak from the engine. The gases were not only damaging to the car, but they were also polluting the environment. The PCV system was created to eliminate these harmful issues.

Indications the Crankcase Ventilation Valve has Malfunctioned

When the crankcase ventilation valve malfunctions, it is unable to move the gases to the intake manifold. Instead, the gases are stuck in the engine system. These gases can lead to engine damage and possibly complete failure.

The positive crankcase ventilation system has two components that can malfunction. They are the crankcase ventilation valve and the PCV filter. If either one of these fails, you will experience a problem.

Signs your crankcase ventilation valve has failed

When the crankcase ventilation valve fails, it will either stay closed or open. The symptoms you experience can mimic signs of MAF failure. Common symptoms of crankcase ventilation valve failure include those listed below.

  • Excessive Oil Consumption: A malfunctioning crankcase ventilation valve can cause your BMW to use more oil than usual. You may notice a puddle of oil under your car if the valve has failed.
  • Poor Performance: The buildup of gasses caused by the failing crankcase ventilation valve can inhibit the performance of your BMW.
  • Contaminated Filter: When the valve fails, it can contaminate the filter. A contaminated filter can lead to an increase in fuel consumption.
  • Rough Idling: A faulty valve will not be able to supply the proper amount of airflow between the intake manifold and the crankcase. This can cause your BMW to idle roughly.
  • Engine Misfires: An improper air to fuel ratio will cause your car to run either lean or rich. This can produce engine misfires.
  • Exhaust Smoke: Crankcase ventilation valve failure can cause the crankcase to make oil enter into the combustion chamber. The oil is then burned inside the engine and smoke is forced out of the exhaust pipe.
  • A Bad Air-to-Fuel Ratio: Depending on the failure, the valve can be providing too much air or not enough air.
  • Trouble Starting the Engine: The crankcase ventilation valve has to be working properly to remove gases from the crankcase. If the gases are not removed, it can lead to contamination and sludge buildup.
  • Failed Emissions Test: If your BMW has failed an emissions test, it could be due to a malfunctioning PCV Valve.
  • Check Engine Light: Your BMW’s check engine light can be triggered by several different reasons. One of these is a malfunctioning crankcase ventilation valve.

Is it safe to drive with a malfunctioned crankcase ventilation valve?

Your car will usually run with a malfunctioning crankcase ventilation valve. However, we do not recommend doing so. Driving your BMW with a faulty PCV Valve can cause permanent engine damage and an expensive rebuild.

Replacing the Crankcase Ventilation Valve

At Hayes European, our highly-skilled and BMW Filter Cleaning experienced mechanics understand BMWs. You can be certain that you will receive the best service at an affordable rate.

Staying current on your regular maintenance will often prevent crankcase ventilation valve failure. The valve is a component that is scheduled to be replaced during your scheduled maintenance plan every 30,000-60,000 miles.

If the crankcase ventilation valve in your BMW has malfunctioned, do not wait to have it replaced. Doing so can cause even more damage. Our technicians can replace the valve quickly and get you back on the road.

If you need your BMW serviced or repaired and are in the Santa Cruz, Aptos, Soquel, or Capitola, CA areas, contact Hayes European. You can reach us on 831-269-5858 or come visit us at 1010 17th Ave., Santa Cruz, CA.