Glossary · variable-cam-timing
VANOS — BMW's variable cam-timing system (1992–present)
VANOS is BMW's hydraulic variable cam-timing system, introduced on the M50TU in 1992 and now standard across the inline-six range as double-VANOS.
By Christoph Paterok · Published 2026-05-19 · Verified 2026-05-19
VANOS is BMW’s marketing name for variable Nockenwellensteuerung — variable camshaft control — the hydraulic system that rotates one or both camshafts relative to the crankshaft to advance or retard valve timing. It is the dominant cam-phasing technology across the modern BMW range and the reason most BMW engine pages on this site reference a VANOS solenoid failure mode as a routine 80,000-mile service item.
Single-VANOS vs double-VANOS
Single-VANOS was introduced in September 1992 on the M50TU inline-six, making the M50TU BMW’s first variable-valve-timing engine. Single-VANOS rotates only the intake camshaft; the exhaust camshaft stays at a fixed timing relationship. The system uses pressurised engine oil, modulated by a DME-controlled solenoid, to drive a helical-spline cup along the front cam sprocket. As the cup slides along the helical teeth, the camshaft rotates relative to the drive gear — up to 40 degrees of crankshaft rotation on the intake side.
Double-VANOS adds an independent actuator on the exhaust camshaft, debuting on the S50B32 in 1996 (E36 M3 Euro-spec) and reaching road-car inline-sixes with the M52TU and M54 in 1998. Every subsequent BMW petrol inline-six — including the BMW N52 that anchors this site’s bulletproof-engine thesis — runs double-VANOS. Many pair it with Valvetronic from 2001 onward.
The canonical failure mode
The VANOS solenoid is the most commonly reported VANOS-related repair. Editorial sources and multiple forum threads on PistonHeads and e90post place solenoid degradation at 50,000–80,000 miles, with oil varnish and particulate clogging the small solenoid screens. Fault codes 2A82 (intake) and 2A87 (exhaust) are the BMW-proprietary identifiers for double-VANOS solenoid failure; OBD-II generic equivalents include P1520 and P1523. Symptoms include rough idle, low-end torque loss, hesitation below 3,000 rpm, and a cold-start rattle that fades after warm-up. Pierburg-branded OE-equivalent solenoids are widely preferred over no-name aftermarket — three separate forum threads document aftermarket solenoids causing worse symptoms than the worn units they replaced.
See the VANOS Grounding Page for the canonical fact grid and the full engine application list.