VANOS Adjuster Unit (Complete), New - E46 M3, MZ3, Z4M, S54

VANOS (or VAN0S) is BMW's variable valve timing system. The VANOS unit is basically a pump and solenoid that rotates the camshaft to make more torque at various RPM. Having a variable camshaft means the M3 S54 engine can make a lot of power in the high RPM without feeling too sluggish in the lower RPM. Obviously any problem with the S54 VANOS unit will have a major effect on performance and drivability, including misfires, fault codes, rough running, sluggish performance, poor fuel mileage, and the dreaded "marbles in a can" rattle sound.

The S54 VANOS is made up of three major parts: the adjuster units (1 for each camshaft), solenoid pack, and the oil supply and pressure system. The part on this page covers all three. Typically, the adjuster unit 80-100,000 miles. The solenoids that drive the VANOS adjustment unit are the first to need replacement, usually by 60,000 miles. They will most often be associated with "VANOS jammed" fault codes. The solenoids can be replaced independent of the complete VANOS unit, although new ones are included with a complete VANOS unit like on this page, or the Dr. VANOS unit.

The telltale rattle of VANOS failure is not always the best indicator of a VANOS issue, especially on the noisy S54 engine. In addition to the VANOS, other parts make similar noises: valve rocker arms/tappets, timing chain, and timing chain guides. A BMW specialist shop should have more advanced tools that can tell which part of the VANOS needs replacing. It's not uncommon for high mileage S54, especially if service was ignored or deferred, to need more than just the VANOS unit replaced. Other wear items or weak areas include the bolts holding the sprocket to the camshaft, the hub on the exhaust camshaft that drives the VANOS oil pump, the aforementioned chain guides and valve adjustment, an VANOS oil lines. All of these parts are available separately.

This item is a complete S54 VANOS unit by BMW and carries a two year warranty from BMW North America.