DrVanos.com

The 1999 - 2003 US and Euro E39 M5 (S62) uses a dual vanos for each bank of cylinders making it a fairly complex system. While the vanos units themselves are quite reliable and should last the life of the car in most cases, the solenoids can cause various problems which can be mistaken for a vanos failure. While we do offer a rebuild service for the M5 vanos if needed, most vanos related issues can be addressed by simply repairing or replacing the solenoids. 

Each vanos has a solenoid pack containing 4 individual solenoids. Each solenoid has 2 O-Rings which can harden and fail over time causing various performance problems. We offer a solenoid repair kit consisting of 16 Viton O-rings and 2 new gaskets for the cover plate. This is a great preventative maintenance upgrade and can be easily done in a couple of hours without any special tools. 

 These units are also well known for the annoying rattling or diesel sound heard at idle and low RPM's. It needs mentioning that the rattling noise is not directly related to the failing seals, and is a separate issue of it's own. It will not harm the engine and is not an indication of the health of the vanos, but is simply an engineering oversight that can be easily fixed with some minor internal modifications.

 The common M5 'diesel rattle' can be attributed to the splined gears that fit at the back of the vanos, connecting the vanos to the cam gears. Each splined gear has a bearing assembly inside which allows it to spin freely with the camshaft. These bearing assemblies are designed with a very loose tolerance from the manufacturer, causing them to rattle or resonate at certain RPM's. At DrVanos we slightly modify these bearings to bring the tolerances much closer together for a tighter fit. By reducing the tolerances in the bearing assembly, the gears no longer resonate and the diesel rattling is virtually eliminated. This is a permanent modification that will last the life of the car.

The removal and installation of the splined gears is a fairly complex procedure and not practical for the average DIY owner, but a qualified BMW technician should be able to replace the gears in a few hours. If you are interested in more information about reducing the rattle on your M5 please contact us for more information. We can supply rebuilt gears on a core exchange basis at a very reasonable price.