Repairing the VANOS seals on BMW’s M52TU/M54/M56 engines

Since 1992, BMW has used a variable valve timing unit, called VANOS (an abbreviation for the German, variable Nockenwellensteuerung), which advances or retards the timing based on readings from the ECU in order to optimise performance. Initially, a single VANOS setup adjusted only the intake timing, but BMW introduced a double VANOS setup in 1996 to adjust both intake and exhaust timing. The unit sits at the front of the cylinder head, and the readings from the ECU send a signal to the VANOS solenoid, which then adjusts oil pressure to operate two pistons inside the unit. The pistons in turn adjust the timing by advancing or retarding the camshafts. Continue reading “Repairing the VANOS seals on BMW’s M52TU/M54/M56 engines”