BMWs VANOS Explained
In the following paragraphs we will endeavor to explain the basics of what VANOS is. VANOS stands for VAriable Nockenwellensteuerung (which translates from German to English to variable camshaft control).
This is a system originally developed by BMW for models produced after and during 1992.
There are 2 types of single, VANOS and double. The very first engine to feature VANOS was the M50 (found in a variety of models), double VANOS first appeared in the S50B32 (used in the M3 Evo,Z4M, Z3M and M52) in 1996.
Single VANOS uses a hydraulic and mechanical adjustment to the position of the intake camshaft against the crankshaft.
According to the engine speed and accelerator pedal position the career is adjusted. At low speeds the intake valves are opened later which contributes to the renowned 6 cylinder smoothness and also helps the idle.
Once speeds are increased the intake valves open earlier allowing more torque, less fuel consumption and minimize emissions (this is because the exhaust gasses re-circulate inside the combustion chambers).
Once again open later at high speeds the intake valves. This lets full capability to be achieved.
Precisely what is VANOS, what does it do for your engine and how will it work.
According to speed and the accelerator pedal position, double VANOS works much the same as single VANOS, however whilst the one system uses two fixed points inside the RPM range, the double system make use of a continuous adjustment, again.
Double VANOS also extends to the exhaust camshaft as well. Torque is further increased and emissions are further improved as a result.
Whilst VANOS is often reliable, age related problems can mean repairs are necessary. The most prevalent problem is the rattle that is found in the upper valve train assembly.
If the mileage of the engine is around 100k, listen carefully when buying. The only method to prevent failure is to replace the seals with aftermarket items. Other notable issue is the piston seals can fail. This is due to age and mileage. In case the engine is of high mileage then be sure to alter the piston seals, once again, prevention is better than cure so.
Single VANOS is located in the following engines:
Double VANOS can be purchased in the following the engines:
Please do not forget that some variances in the specification appear in the US models.