BMW Vanos Repair
Many newer BMWs need repair of the VANO system, this article explains what it is and symptoms of failure. You may have heard the term ‘variable valve timing’ used in vehicle commercials and press releases. Most late-model vehicles are equipped with variable valve timing, which provides better control of the valvetrain, resulting in increased fuel economy and engine performance. VANOS is the name BMW has given its variable valve timing system.
BMW introduced the VANOS system beginning in 1992. The name comes from the German term “variable Nockenwellensteuerung”, meaning variable camshaft control. From the name, it’s easy to ascertain that the VANOS system continuously adjusts the camshaft. Depending on the speed of the engine, the position of the camshaft will be moved so that the valves can be opened either early or late. Fine tuning of valve operation is what allows the VANOS system to provide better fuel economy, lower emissions and a smoother running engine. The system uses engine oil pressure to operate and continuously adjusts as the engine runs. Double-VANOS was introduced in 1997, and is used to control the amount of exhaust gas recirculation (EGR) into the engine, for enhanced fuel economy.
Unfortunately, the VANOS system has quite a few problems. Inside the adjustment mechanism, there is a set of seals that hold oil pressure, enabling the camshaft to change position. From the factory, these seals are made of an inferior material that does not stand up well to oil saturation and temperature fluctuation. When the seals begin to fail, the VANOS system is unable to operate properly. Also, the bolts holding the VANOS unit in place have also been known to come loose, or in some cases, break. BMW recalled 156,000 vehicles due to bolt issues.
BMW VANOS problems can lead to symptoms such as:
- Increased fuel consumption
- Bogging or hesitation
- Sudden power surges
- Loud idle/engine rattle
- Loss of power
In most cases, the VANOS unit will need to be removed from the engine to confirm failure. The original BMW seals begin to deteriorate after 20k miles or so. Because of this, the chances of your unit being faulty are quite good. If you bought your BMW used, you may not even be aware that some of these symptoms are abnormal.
Rebuilding or replacing the VANOS with an upgraded unit, is the only route for proper repair. Replacing the unit is not an easy task. It should be left to professionals (such as us) to ensure the job is done correctly, the first time. Repairing your VANOS system will restore your engines performance, and allow your car to drive the way BMW intended.
If you have any questions about getting your BMW repaired let us know, we have ASE certified mechanics on staff and are conveniently located off the I-15 in West Jordan, UT.