Variable Valve Timing Actuator: Service and Repair
Installing And Removing Or Replacing VANOS Adjustment (S50 US):
- Remove complete air guide for alternator.
- Remove fan with special tools 11 5 030 and 11 5 040.
Caution! Left-hand threads.
- Brace pulley with special tool 11 5 030 and unfasten cap nut from water pump.
- Remove fan wheel and fan coupling from water pump and remove together with fan cowl.
Installation:
- Tighten down fan with special tool 11 5 040.
Tightening torque = 40 Nm.
Note: 40 Nm tightening torque is equal to 30 Nm on scale of torque wrench.
- Remove cylinder head cover.
- Remove spark plugs.
Removal:
- Removal of VANOS adjustment unit is described separately from installation. Assembly sequence for removal and installation is different.
- Unscrew oil pressure pipe.
- Disconnect solenoid-valve plug-in connection.
- Fit suspension lug.
- Remove cable duct.
- Pull off plastic cover for intake camshaft.
- Rotate engine engine-wise until cam tips on intake and exhaust camshafts on 1st cylinder face one another.
- Pull dust guard out of the special tool bore.
- Secure crankshaft in TDC position with special tool 11 2 300.
Caution! Remove special tool 11 2 300 before switching on the engine.
- Unscrew studs.
- Secure camshafts with special tool 11 3 240.
- Unfasten screw plugs.
- Unfasten sprocket screws on exhaust camshaft.
- Press top of chain tensioner downwards and lock with special tool 11 3 290.
- Unscrew nuts.
- Fit special tool 11 5 490 to exhaust camshaft gear.
- Using special tool 11 5 490, rotate sprockets and secondary chain clock-wise, at the same time removing the VANOS adjustment unit.
Installation:
Installation of VANOS adjustment unit is described separately from removal. Assembly sequence differs between removal and installation.
- Rotate sprockets and secondary chain clockwise with special tool 11 5 490 until detent position is reached.
- Press back spline shaft on adjustment unit (1) as far a detent in housing (2).
- Note dowel sleeves (1).
- Coat contact edges of joint between cylinder head and VANOS adjustment unit with 3 Bond 1209 sealing compound.
- Replace seal.
- Fit VANOS adjustment unit.
- Rotate spline shaft (1) until internal spline engages.
- Fit special tool 11 5 490 to exhaust camshaft.
- Rotate chain and gears with special tool 11 5 490 counter-clockwise until spline shaft engages in internal spline of sprocket (2).
Caution! Always ensure that the FIRST suitable tooth engages.
- Slide VANOS adjustment unit towards cylinder head.
- Guiding the helical bevel splined shaft into the helical bevel splined sprocket turns the sprockets with mounted chain counterclockwise.
- Rotate chain and gears with special tool 11 5 490 counter-clockwise.
- Remove special tool 11 5 490.
- Tighten down VANOS adjustment unit.
- Remove special tool 11 3 290.
- Unfasten screw connection (3).
Caution! Strong spring force.
- Remove spring (2) and piston (1).
- Install special tool 11 3 390 in chain tensioning sleeve (1).
- Fit adjusting screw to tensioning rail.
- Preload tensioning rail with special tool 11 3 390 by rotating the adjusting screw with special tool 00 2 050 standard torque wrench to 1.3 Nm.
- Tighten sprocket on exhaust camshaft in two passes.
Tightening torque:
Application torque = 5 Nm
Jointing torque = 20 Nm
- Remove special tool 11 3 240.
- Remove special tool 11 2 300.
Note:
- If work was carried out on the camshafts previously, rotate engine twice engine-wise then check camshaft setting.
- Secure crankshaft with special tool 11 2 300 in TDC position of 1st cylinder.
Caution!
- Do not turn the engine back.
- Remove special tool 11 2 300 before switching on the engine.
- Fit special tool 11 3 240 to camshafts.
- The camshaft setting is correct if the special tool 11 3 240 can be fitted to the cylinder head without gap.
- Remove special tool 11 3 240.
- Unfasten and remove special tool 11 3 390.
- Install chain tensioning piston (1) with guide lugs engaging in tensioning rail.
- Install spring (2) and screw connection (3) with new seal.
Tightening torque = 50 Nm.
- Install plugs with new sealing rings.
Tightening torque = 50 Nm.
- Check function of VANOS adjustment unit.
- Fit special tool 11 3 450 with banjo bolt on oil pressure line.
- Connect up compressed air (2... 8 bar).
- Measure gap (x) between secondary tensioner and edge of sensor gear.
- Note down distance 1.
- Connect special tool 12 6 410 to the solenoid valve plug connection for VANOS.
- Connect positive clip to battery connection point.
- To adjust camshaft, connect negative terminal to vehicle earth.
Caution!
- Reversing terminals on special tool will destroy installed diode on VANOS solenoid valve. Solenoid valve remains serviceable but current spikes can give rise to faults in vehicle circuit.
- Measure gap (x) between secondary tensioner and edge of sensor gear.
- Note down distance 2
- Determine control travel:
- Distance 2 - distance 1 = length of stroke.
Caution!
- If adjustment stroke is less than 8.5 mm, VANOS adjustment unit must be readjusted.
- Remove special tools 11 3 450 and 12 6 410.
- Fit cable duct.
- Fit suspension lug.
- Fit oil pressure line with new seals.
Tightening torque = 32 Nm.
- Install solenoid-valve plug-in connection.
- Remove special tool 11 2 300 (plug mandrel).
- Assemble engine.