It is a well-known fact that BMW cars are developed with high quality, cutting edge technology, capable of ensuring the full satisfaction of its clients. BMW provides the best in engineering on their vehicles, but even with all of that, sometimes things go wrong.

Our years of BMW experience at Foreign Automotive know that BMW machinery is complex. Therefore, it needs specific maintenance services as time goes by so the car can keep operating at its optimal capacity.

This brings us to one of the most common issues that many BMW models faces over time, sometimes due to poor maintenance, and that is a failure in the positive crankcase ventilation valve (PCV valve). This valve plays a vital part in the engine function, and therefore its failure might bring irreversible consequences to your BMW, shortening the functionality and the life span of your car when left unaddressed.

What’s the PCV Valve?

The PCV valve was designed to solve an engine related issue. As it turns out, car engines in the late 1950s tended to release leaked unburned fuel in the form of “blow-by gases”. These gases were highly toxic and started to harm the environment, as well as fill cities with toxic fumes.

These vapors and fumes are the result of an air-fuel mixture originated from several powerful inner explosions that releases fuel energy and goes into the cylinders. Those gases could not be fully contained within the car, either. The gases caused problems with the engine because of the toxic substances contained within, acting like an acid that corrodes any engine metal component they touch.

In 1961, the PCV valve system was rolled out to solve this problem by simply using the vacuum of the engine. It extracts blow-by gases from the crankcase, then pushes those gases down the intake manifold and back into the combustion chambers so they are fully burned. Unfortunately, when not given proper maintenance the PCV valve will eventually fail.

PCV Valve Failure Consequences

Now that you know the importance of the PCV valve system in connection to the engine’s functioning, you can better understand the implications of the failures of this system.

The number and type of symptoms your BMW might present when a PCV valve malfunctions mainly has to do with the pressure buildup relief that stops functioning when the valve stops working properly. However, depending on which part the valve gets clogged, you might be presented with specific issues that you can recognize the symptoms of.

With the valves clogging, or being stuck in the closed position, the symptoms might include:

  • Increased pressure in the engine
  • Oil seals/gaskets malfunctioning
  • Leaking of engine oil
  • Buildup of sludge and moisture in the engine
  • Black smoke originating from engine

On the contrary, should the valve be stuck in the open position, or if there is a disconnection or possible rupture of the system hose that produces a vacuum leak, these would be the symptoms:

  • Engine misfiring when idle
  • Lean air-fuel mixture
  • Engine oil found in the PCV valve or hose
  • More oil being consumed than usual
  • Engine starting hard
  • Engine idling rough
  • “Check engine” light triggered

On the environmental side, a malfunctioning PCV valve is prone to cause engine oil and air pollution due to the building up of sludge, leaking of oil and the high consumption of fuel, among other problems.

The economical aspect also gets compromised as a PCV valve related failure usually leads to pretty expensive repairs as the toxic gases can corrode your engine from the inside out. That’s why it is best to detect these problems in an early stage by performing a few general inspections. There is still a lot of misinformation and ignorance about the importance of regular car maintenance, but by depending on the experts who know BMWs the best, you can help avoid these problems.

PCV Valve Maintenance

Fortunately, as mentioned before, PCV system failures can be prevented with routine inspections that put a focus on detecting these problems early. Because BMWs are such intricate pieces of machinery, it’s important to turn to the experts.

If you live in Kitchener, Waterloo, Cambridge or Ontario and the check-engine light illuminates on your dashboard, feel free to give us a visit at Foreign Automotive. We have the best BMW specialists that will properly code, read, diagnose, and replace your PCV system if necessary. We’re dedicated to BMW maintenance and repair so you can feel secure in knowing your Bimmer is in good hands and will be back on the road soon!

* BMW E46 image credit goes to: kurmyshov.

* BMW 3 Series image credit goes to: Stratol.