Having any type of oil-related issue in your BMW is not a good sign and is something that should be addressed immediately. Taking proper care of the oil and oil systems leads to a healthy and happy BMW engine for better efficiency, longevity, and cleaner running.
When you’re referring to the air-oil separator it can mean different things for different vehicles. In regards to a BMW, you are more specifically speaking in terms of the crankcase ventilation system which is also known as the PCV or CCV valve (positive crankcase ventilation valve).
Like most foreign automobiles, BMWs need to be taken care of to avoid complex mechanical issues down the road. This can easily be done through proper maintenance services like oil changes and engine checks. However, over the lifetime of your BMW, some issues may be difficult to avoid, and PCV valve failure could easily be one of them.
Often due to lack of routine maintenance, the vehicles PCV valve will begin to fail and be left unnoticed. Once that happens it will dramatically impact the longevity of the vehicle’s engine. Knowing how vital aspects of your BMW work together, how to recognize issues early on, and how to address those issues are all key parts in maintaining your foreign automobile. Let’s take a look at those signs.
What Does the Crankcase Ventilation Valve Do?
BMWs crankcase ventilation system is in place in order to relieve pressure off the crankcase and to redirect combustion gases. This works by separating the liquid oil from the air that is inside the engine as well as the intake manifold. When the oil is removed from the intake air, it should then be returned to the oil pan. The CCV valve will then also take any remaining oil vapors and recycle them back into the vehicle to be used in the combustion chamber.
This is vital to your BMW’s engine life because, without the crankcase ventilation system, your vehicle’s engine would leak excessive amounts of unburned fuel and oil. This excessive exhaust from the engine can then pollute the air as well as corrode the vehicle’s engine.
Signs of PCV / CCV Failure
The CCV system itself is made up of a valve that is responsible for separating the oil from the air and controlling the flow of gases and 4 hoses to connect the vehicle components together. Since there are multiple components that comprise the PCV valve or CCV system, there are different ways your BMW’s air-oil separator can fail as well as different signs and symptoms that go along with it. Knowing the warning signs are important in order to avoid overly-high oil consumption, burning oil, loss of engine power, misfiring, and/or high carbon deposits.
The basic aspect that you will be dealing with when the CCV system isn’t functioning properly is pressure buildup. However, how the problem presents itself will vary depending on if the valve is clogged, stuck in the closed position, stuck in the open position, or a hose has a leak or tear.
General indicators of an air-oil separator failure include the check engine light illuminating on the gauge cluster, excessive amounts of oil being used, spark plugs coated in a layer of engine oil, sludged up oil, white smoke from the exhaust pipe, and whistling noises while driving.
If your BMW is experiencing a CCV valve failure due to the valve being clogged or being stuck in the closed position, your vehicle is more likely to experience engine oil leaks, buildup of sludge or moisture in the engine, black smoke coming from the engine, and/or increased engine pressure.
If the CCV valve gets stuck in the open position, there may be a torn hose in your vehicle. It may be more likely to exhibit signs such as engine misfiring or rough engine running when in idle, hard engine start, engine oil in the PCV valve or hoses, lean mixture of air and oil, or any of the general indicators listed earlier.
Knowing the signs will enable you to catch an issue related to your BMW’s PCV valve early on and will prevent things like engine oil and air pollution as well as keep your vehicle’s engine running with the best efficiency.
Leave it to the Experts
If you think you might be experiencing a PCV valve failure in your BMW, it is best to have a trusted mechanic take a look in order to properly diagnose the issue. If you have the knowledge base and feel comfortable checking to see where the problem may be originating you can do so, but often times when dealing with a PCV valve failure you will need to remove and replace different vehicle parts. This can be difficult and labor intensive and is often times best left to professionals.
The best way to avoid an air-oil separator failure is to have a mechanic you trust perform routine maintenance on your BMW to catch possible problems early on or avoid worse issues altogether. If you live in or around Norwood, Westwood, Walpole, Sharon, Canton, Medfield, Needham, Dover, or Boston, MA, consider the experts at Revolution Automotive Services for any and all questions you may have regarding your BMW.
* BMW M2 image credit goes to: teddyleung.