BMW is arguably one of the best cars in the market. Its high performance has made it one of the most sought-after vehicles across the globe. However, like other vehicles, the vehicle’s durability can come into question because parts can naturally begin to develop faults after extended use.
In order to ensure the longevity of your vehicle, faults must be attended to immediately. Amongst many issues that a BMW can experience is the failure of the VANOS system. This type of problem requires urgent attention to avoid further damages that can hinder the smooth operation of your BMW.
The VANOS System
The BMW VANOS system is a feature created by engineers to improve their models’ performance and fuel economy. The system was introduced in the ‘90s, and it modified the engine’s intake and exhaust valve to ensure that both parts actively open and close during driving, thereby improving engine performance.
The introduction of the system helped optimize engine performance, increased vehicle torque, and gave the vehicle a smoother idle. It also helped to lower exhaust emissions, thereby reducing the environmental pollution.
The system improved the engine performance by adjusting the valve timing whenever it notices changes in your speed to regulate the rate at which fuel and air enter your engine. The VANOS system has a long coil of wire wrapped around it called the solenoid. The solenoid controls the amount of oil pressure applied to control the movement of the camshaft gear outward or inward, thereby effectively controlling the valves’ timing.
The result is that the optimal amount of fuel and air needed by the engine is sent to it to ensure the efficient running of your vehicle.
Causes of VANOS System Failure
There are two major causes of VANOS system failure.
- O-ring Failure: The piston is sealed by the O-rings, which are made from rubber. The exposure of these rings to extreme conditions causes them to wear down and fail over time. The failure of these rings causes the failure of the VANOS system piston and, consequently, the engine’s failure.
- Clogged Solenoids: The solenoid is responsible for transporting oil through the VANOS system. Over time, the solenoids may become clogged, which cause the solenoid to fail, thereby failing the VANOS system.
Symptoms of a VANOS Failure in Your BMW
The VANOS system in your BMW can fail at any time, thereby preventing the optimal functionality of your engine. Depending on the VANOS system in your vehicle, certain symptoms will be noticed when it fails.
You may notice the following symptoms in a single VANOS system:
- lowered horsepower
- rough idling
- poor driveability
- low fuel efficiency
The following symptoms may be apparent in a double VANOS system:
- loss of low range power
- engine hesitation
- rough idling
- trouble cold-starting
- sluggish acceleration
Other symptoms that will be evident are slow acceleration, decreased driveability, rattling noises, loss of horsepower and torque, slow cold starts, erratic idling, excess fuel consumption, etc.
Expert mechanics recommend that the VANOS system seals should be replaced after 50,000 miles for optimal engine performance. And the replacement of the system should be done after every 70,000 miles.
Manfred’s Import Auto for Quality BMW Repairs and Maintenance
Whenever your BMW’s VANOS system fails, it is best to leave it to professionals to avoid causing more damage in the repair process. 
Ensuring that the problem is promptly rectified will also help prevent other damage to your vehicle. To do this, you need a reliable auto repair shop.
At Manfred’s Import Auto, our certified technicians have decades of experience working with European vehicles and provide drivers with complete maintenance and repairs. If you live around Barrington, Crystal Lake, Fox River Grove, Lake Forest, Lake Zurich, and Cary, IL, and you suspect that the VANOS of your BMW may need to be looked into or replaced, feel free to reach out to us.
We employ the latest factory-grade tools & equipment to ensure quality service. Whether your car is due for service or emergency repairs, our ASE-certified mechanics have you covered. Please call or visit our shop today to schedule an appointment or learn more about our services and maintenance programs.
* BMW Logo image credit goes to: vesilvio.
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