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As you drive your BMW for a number of years, extra maintenance and repairs may become necessary. One of the most common repairs is to fix leaks in the vacuum hose. BMWs are luxury vehicles that are built for performance, each uniquely made to have a sleek exterior with a beautiful and comfortable interior. Under the hood, you will find an engine that is built to perform and built to last, but all vehicles need proper maintenance to prevent things like leaks in the vacuum hose. Below you will find out more information in regards to the vacuum hose and what signs to look for that will let you know it is leaking.


A majority of vehicles that run on gas are going to have some type of vacuum hose in it or even multiple hoses. This includes your make and model of BMW. The age of your BMW will determine how many vacuum hoses you have. The older models tend to have more vacuum hoses because, at that time, the systems under the hood were very complex and required multiple connections in order to keep everything working properly. As the newer makes and models of BMWs came onto the market, the systems are still complex, but the technology has advanced enough to utilize fewer vacuum hoses. Regardless, your BWM will still have at least 1 vacuum hose.

With all that being said, the vacuum hoses are used to transmit vacuum from the intake manifold to a part which requires vacuum power. The intake manifold is one of the main parts that gives power to other components, because it distributes the combusted fuel/air mixture required for the full function of your BMW.

Some parts that require the use of a vacuum hose are the PCV valve, the HVAC controls, the brake booster, and the heater control valve. It is not efficient for all of these parts to be connected directly to the intake manifold. So this is where the function of vacuum hoses come in. They enable all the parts connected to them to maintain proper efficiency.


The first sign that will indicate to you that there is something wrong with the vacuum hoses is that the check engine light will come on. There are multiple sensors surrounding all the vacuum hoses. So if there are any leaks, the sensors will pick up on it and be alerted. The leak will then be alerted to you through the check engine light. It is important to pay close attention to that check engine light because it could be letting you know about something simple like a vacuum hose leak or something major.

The second sign that will alert you to a vacuum hose leak is that the engine will not run smoothly. The engine will run roughly because one or more of the parts that are connected to a vacuum hose is not getting the necessary power from the intake manifold. So, due to this lack of power, the connected parts are not going to properly function. Your engine will run roughly. In addition to problems with the engine, there will be a rough and inconsistent idle.

The third sign that will indicate a leak in the vacuum hose is that your BMW engine will not power up. This will occur if the leak is large or if the leak has been occurring for a long period of time without being addressed. The leak will cause the pressure in the hoses to be too high. This will lead to the head gasket being pushed out. When this happens, the cylinder head hardware can break and cause detonation and combustion to happen inside of the engine as opposed to the combustion chamber. If this were to occur, you would be at risk for potential injury due to a crash caused by an incorrect detonation.


If you notice any one of the three previously-mentioned signs of a vacuum hose leak, it is imperative to bring your BMW in for servicing. At Fast Lane European, located in San Jose, CA, we specialize in all European vehicles, including BMW. Give us a call and schedule an appointment with one of our trained and certified technicians. We use the most up-to-date diagnostic tools to locate the vacuum hose leak and identify any other parts that may be damaged due to the leak. We will review your options for repair and only move forward with the tasks you approve. We value our relationship with you and want what’s best for you and your BMW.