BMW Vanos Seals Solutions
Do you own one of the below BMW 6-cylinder cars, 1993-2006? If so then your vanos, engine variable valve timing unit, is most likely failing. These vanos units have been consistently diagnosed to fail due to deteriorating piston seal O-rings. The O-rings are made of a material that is failing in the engine environment. This causes the vanos piston seals to lose their sealing function and for the vanos unit to fail.
BMW does not provide the vanos seals separately. It sells rebuilt vanos units for ~$500. New rebuilt vanos units are supplied with the same failing O-rings and have been found to significantly fail in 20k miles (32k kilometers).
Vanos seals repair kits are now available from Beisan Systems. They incorporate upgraded O-rings to address the failure mode and replacement Teflon seal rings.
Symptoms
Overall loss of torque and power, particularly in the lower RPM range, < 3k. Bogging then surging at 3k RPM. Uneven power distribution and RPM transition. Engine hesitations in the lower RPM range, < 3k. Louder idle and intermittent idle RPM hiccups. Difficult takeoffs. Loss of power and bogging when AC on. Increased fuel consumption. Vanos fault codes.
Double vanos cars with the M52TU engine (98/99-00) experience cold weather cold start idle jolts and possible stall.
Vanos Seals Repair Benefits
Overall increase in torque and power, particularly in the lower RPM range, < 3k. Resolution of bogging then surging at 3k RPM. Smooth even distribution of power and RPM transition. Resolution of engine hesitations in the lower RPM range, < 3k. Quiet stable idle. Smooth easy takeoffs. Improved performance when AC on. Reduced fuel consumption, by ~10%. Resolution of vanos fault codes.
Resolution of double vanos M52TU engine (98/99-00) cold weather cold start idle jolts and possible stall.
Vanos Seals Failure Affected Automobiles
Single Vanos
BMW 6-cylinder engines M50TU, M52, US S50, S52, 1992-1999
3-series E36 93-97, 5-series E34 93-95 / E39 96-98, 7-series E38 95-98, Z3 Roadster 2.8 E36 96-98, EU Z3 Coupe 2.8 E36 96-98, US M3 E36 94-99, US Z3 M E36 98-99
Double Vanos
BMW 6-cylinder engines M52TU, M54, M56, 1998-2006
3-series E46 98-05, 5-series E39 99-03 / E60 & E61 02-05, 7-series E38 98-01 / E65 & E66 02-05, Z3 E36 98-02, Z4 E85 02-05, X3 E83 03-06, X5 E53 00-06