The VANOS system found in BMW engines is a great feature, keeping your power curve smooth and responsive especially in lower to mid RPM range. What usually goes unnoticed is the gradual loss of power within this range as the vehicles age due to slowly failing seals within the VANOS unit. The way the VANOS system works is based off of oil pressure triggered by a solenoid that allows for a small range of timing degree adjustment, this is where the power curve is affected. When the seals begin to fail (all of them do) there is less pressure to advance the timing reducing the power in that low to mid range. Because this happens slowly its very hard to notice a difference until you refresh your VANOS unit, then you easily realize the response you've been missing.

The main reason all of the VANOS units will eventually fail is because the material used for the sealing rings from the factory is not designed for that type of environment. When this happens the only option that BMW leaves you with is buying a new and expensive VANOS unit with the same sealing rings that failed in your original unit.

There are a number of symptoms that will plague your car as a result of these failing seals such as erratic idle, engine hesitation, stalling, and increased fuel consumption to name a few. If you've been chasing down any of these symptoms with no fix then this could be your issue. 

While you 're replacing the seals in your VANOS unit it a good time to install anti-rattle spacers to tighten up the gaps in your stock assembly and get rid of that noisy Vanos clatter.

Seals & O-rings:

The engineering team here at ECS work diligently to offer a much better option to bring your VANOS unit back life. The seals  were the main focus of this project since the OE units are built with Buna-N rubber o-rings instead of the ECS supplied Viton rubber o-rings. The Buna-N material quickly hardens from the heat and chemical exposure within the engine, where the Viton is significantly more resistant to these chemicals. We also used this knowledge when it came to the commonly failed o-rings found on the VANOS seal plate, replaced at the solenoid.

Rattle Repair:

When it comes to the VANOS rattle this is commonly described as "marbles in a can", and can be heard throughout the different RPM ranges depending on the engine. Our rings and washers are precision ground from hardened steel to resist wear and deformation keeping your VANOS rattle free. The rattle repair tools are designed specifically for this VANOS anti-rattle repair, design from hardened steel to stand up to the job. Designed with precision to perfectly follow the splines of the shaft for a tight grip when applying the necessary torque to disassemble & reassemble the VANOS transfer gear. The keyed socket was designed with the intent to use a "common" wrench so this can be completed at home in your garage.    

When Servicing your VANOS unit we recommend getting everything you need to replace on the way to service which includes an oil change and valve cover gasket set. Fresh oil and gaskets is the best way to start off a fresh rebuild of any kind giving you the maximum performance of your freshly serviced components.

Don't forget to check out our rebuild PDF to make sure you have everything to get the job done and eliminate the rebuild guess work.