Double VANOS seals (M52TU / M54)

Engine / equipment

M52TU and M54 six-cylinder petrol with double VANOS (320i–330i E46, 520i–530i E39, 520i–530i E60 up to 2005, X3 2.5i/3.0i, X5 3.0i, six-cylinder Z3 and Z4)

Period mentioned

1998–2006

Symptoms

Loss of torque and pull below about 3,000 rpm, louder or unsteady idle, the engine bogs when the air conditioning is switched on and sometimes VANOS fault codes. On 1998–2000 M52TU engines, jolts or stalling on cold starts.

Possible cause described

VANOS varies intake and exhaust timing with two hydraulic pistons. The O-rings on those pistons lose elasticity and flatten, oil leaks past them and the system cannot reach the requested position. According to the repair-kit maker, remanufactured units use the same original seals.

Check for the garage

Read the engine codes and, at a garage, compare actual and requested camshaft positions in live data. Rule out vacuum leaks and the CCV first, as they cause similar symptoms. On M52TU engines with cold jolts, the kit maker describes a test with the intake VANOS solenoid unplugged.

Cost cited in the source

Seal kit: about $60 in parts according to its maker (US price), plus gasket and washers; labour extra.A rough figure from the original database, not an up-to-date quote.

Sources from the original database