The 1999 - 2003 US and Euro E39 M5 and Z8 (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, 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, but most vanos related issues can be addressed by simply repairing or replacing the solenoids. The next few slides offer specific information for the most common M5 Vanos problems and how to address them. We highly recommend keeping a code reader in the glove box to easily troubleshoot any fault codes generated without the need to take it to the dealer. We can help diagnose fault codes for you and determine the best method for resolving the issue to save you from needless or expensive repairs.

Click the slides below for additional information...

One of the most common problems on the M5 vanos system is going to be a solenoid failure. There are 4 solenoids on a circuit board inside each vanos unit. If one of these solenoids fails it will generate vanos related fault codes, mis-fires and rough idle. At your local BMW dealership this would normally be diagnosed as a complete vanos failure and replacing one or both vanos units would typically be recommended to fix the problem, along with an estimate in the $2k to $6k price range. We offer the option of testing and replacing the faulty solenoids or replacing the solenoid board while leaving the vanos units on the car. This is an easy and relatively inexpensive alternative to a complete vanos replacement and can be done by the average DIY'er in a couple of hours.
Each vanos has a solenoid pack containing 4 individual solenoids. Each solenoid has 2 O-Rings which can harden and fail over time causing oil to leak from the front of the vanos. We offer a solenoid O-ring repair kit consisting of 16 'D' shaped O-rings and 2 new gaskets for the cover plates. This is a great preventative maintenance upgrade and can be easily done in a couple of hours without any special tools. This is a required upgrade for '99-'01 models, and highly recommended on later models as they age. Note that if you are getting a check-engine light you probably have a solenoid failure as well. Click the 'Removing Solenoids' tab on the left information bar for more info about removing the solenoids.
Removing the solenoids is fairly straight forward, but we have some helpful tips to make things easier. The BMW TIS document at the left describes the procedure, but we have a few additional tips for you.
There is NO need to touch the 4 set screws on the solenoid cover (if you have the style with set screws). These are preset at the factory and should never need to be adjusted or removed!
Sometimes the solenoids will practically fall out of their sockets and sometimes they will not budge. We don't recommend using pliers to remove the solenoids as you can easily damage the wiring or diodes. There is a lip on each solenoid just under the rubber grommet that it sits in. You can simply use a flat blade screwdriver and gently pry each solenoid up, starting with the 2 lower solenoids, then the 2 upper solenoids. If this does not work install the solenoid cover and all 5 bolts but leave them slightly loose, leaving a ~2mm gap between the solenoid cover and the vanos unit. Start the engine for 3-4 seconds and this should force the solenoids loose using oil pressure inside the vanos. You may get some oil leakage so be prepared!
The M5 has 4 cam position sensors, one intake and one exhaust for each bank. These are another common failure point on the M5 and will usually start to fail around 80k miles, generating a check-engine light, rough idle and poor performance. If you have a fault code reader you will most likely find a specific fault for a failed CPS, along with the bank and intake or exhaust details. Note that on LHD cars Bank 1 is the passenger side (where the oil fill cap is located) and Bank 2 is the driver side (where the remote battery post is located). Your fault code should specify which bank as well as intake or exhaust side. Note that the cam position sensors are located at the back of the engine next to the firewall, with the intake sensors closest to the center of the engine, and the exhaust sensors will be on the outer side of the engine, near the exhaust headers.
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 related to the failing seals or solenoids, 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 modifications.
 The 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 modify these bearings to bring the tolerances down for a tighter fit. By reducing the tolerances in the bearing assembly the gears no longer resonate and the diesel rattling is reduced considerably. 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. We can supply rebuilt gears on a core exchange basis at a very reasonable price.

Send us your M5 vanos units and we can rebuild them with all new Viton and teflon seals, new gaskets and lifetime solenoid O-rings. We can also test and replace any faulty solenoids if needed as well repair damaged solenoid boards, wires, connectors, etc. Replacement solenoids are $400 each with the rebuild service.

Rebuild service starting at $300 each

If you need a rebuilt or replacement vanos we offer rebuilt vanos units complete with solenoids, ready to install.

$900 each plus a $400 refundable core deposit

The M5 Vanos price includes a fully refundable $400 core deposit for your old vanos. You can return your old vanos to us using the supplied UPS return label in the box and we will refund your $400 core deposit to you within 1-2 business days for a net price of $900.

Having solenoid issues? Send us your solenoid board and we can test and replace individual solenoids with a quality replacement saving you the cost of a full replacement pack. We can also replace broken connectors and wires, fix damaged boards, and replace missing diodes at a very reasonable price.

M5 Solenoids

Price: $400.00 per individual solenoid

Send your solenoids to us at the address on our contact page. When sending your solenoids in for repair, please include your information in the box and we will contact you with an estimate once they arrive.

For those looking for a ready-to-install solution for the M5 'diesel rattling' noise we offer a rebuild service for the 4 splined gears. The gears are modified to reduce the diesel noise significantly both at startup and at idle.

Optionally you can send us your gears for the rebuild service.

Parts and Accessories...

These high quality O-Rings will last the life of the car and are a great preventative maintenance upgrade for any model year M5/Z8. The kit includes 16 O-Rings and 2 cover plate gaskets, enough for both vanos units.
Highly recommended for all model years.

Replacement solenoid cover plate gaskets are often a forgotten item and are needed whenever removing the solenoid cover plate.

Splined gear repair service available! DrVanos offers a replacement spindle service to get you back on the road for a fraction of the cost of a new gear set. Just send your broken gears to us and we can replace the spindle for $45 each. Please note that we do not sell the splined M5 gears outright, but you can buy the spindle for $25 each.


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