BMW E46 M3 – VANOS Repair & Maintenance

The Vanos system in many of BMW’s is an integral system of the engine operation, we will discuss the importance of maintenance and improvements available for the BMW Vanos systems. We see failures of these systems quite often, and in some cases they can be catastrophic. So, there are several steps you can take to not only avoid this, but also upgrade the system for better performance along with peace of mind. “Vanos” is BMW’s name for its variable valve timing units. Vanos units take on various shapes and design according to car year and model (engine model). The vanos discussed here is the S54 (E46 M3), and there are many improvements available. We will be referencing Beisan Systems specifically. They continually provide top quality products, and are very professional in dealing with.

The first item that should be replaced and causes the majority of catastrophic failures is the factory oil pump disc. The clearances of these discs is not ideal direct from production, and what happens is the 2 “ears” of the oil pump drive have the ability to knock back and forth. Over time the ears on the drive can physically break and become lodged in the Vanos unit. Lack of oil pressure quickly damages other components, making it necessary to dig much deeper into the engine to inspect what other items have been affected.

Broken pump disc

The second item we replace while the Vanos unit is disassembled is the bearing inside of the splined shaft. This shaft is what physically causes the camshafts to adjust valve timing. As they wear the bearing clearances become too great, causing the notorious BMW Vanos rattle as it is commonly referred to. We disassemble the splined shafts and change out the bearing races, and add a thicker shim to reduce the axial clearances. This completely eliminates any noise caused by the shafts.


Shaft componentsShaft disassembled








Last but certainly not least, is the Vanos Solenoid Coil Pack. This is the most common failure on the BMW’s, and it is basically inevitable to fail at some point. This is a harder item to diagnose as it causes minor driveability issues, however an automotive enthusiast will notice the slight changes and often contact us with concerns. The reason for failure is a manufacturer defect in how the circuit board is constructed. The fastening points are all located on one side of the circuit board, which allows the opposite end to deflect while the engine is running. This essentially causes a “diving board” effect and allows the circuit board to vibrate very heavily on one end. What Beisan Systems does is drills out a locating pin on the problem side, and installs a fastener to eliminate any potential movement. Illustrated below is the failed solder connections, and a comparison between before and after the fastener is retrofitted.


Failed solenoid contactsSolenoid coil pack








All of these repairs combined, once performed, can make the driving experience of your E46 M3 take on a whole new meaning. The timing is adjusted after installation, which is also often slightly off from factory, making your M3 much more responsive and fun to drive. If you have concerns some of these components may be showing wear or even damage, feel free to contact Haute AG, and see how we can assist you today. We hope this information was helpful, and encourage you to check out Beisan Systems for more pictures and testimonials on their quality products.