Removing Double VANOS Adjustment Unit

Removing and Installing or Replacing Double VANOS Adjustment Unit

Remove intake filter housing with air-mass flow sensor.
Remove fan impeller with fan clutch and fan cowl. Service and Repair
Remove cylinder head cover. Service and Repair
Remove spark plugs.

Removal:
Removal of double VANOS adjustment unit is described separately from installation. The assembly sequence for removal and installation is different.





Detach plastic cover for inlet camshaft.





Unscrew oil pressure pipe.





Mount special tool 11 3 450 with banjo bolt of oil pressure line.





Caution:
Cover double VANOS adjustment unit.
When the compressed air supply is connected, several drops of oil are sprayed out of the bore.





Connect compressed air (2 to 8 bar).





Note:
When the engine is switched off, it is possible that the camshafts are not in their initial positions.
With the compressed air supply connected, rotate the engine to return the camshafts to their initial positions.

With compressed air supply connected, crank engine at least two revolutions in direction of rotation until cam tips on inlet and exhaust camshafts on 1st cylinder face each other.





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.





Detach compressed air connection.

Note: Special tool 11 3 450 still remains fitted.





Caution:
Oil emerges after the plugs are unscrewed. Have cleaning cloths and container ready.
Make sure no oil runs onto belt drive. Remove any remnants of oil immediately with cleaning cloth.
Remove plugs, collect emerging oil on inlet and exhaust sides.





Remove sealing caps with special tool 11 6 170 or with commercially available short flat nose pliers.





Caution: Left-Hand Threads.

Release setscrews on inlet and exhaust sides.





Disconnect plug connections from camshaft sensor and solenoid valves on exhaust and inlet sides.





Unscrew suspension eye.





Release nuts and remove double VANOS adjustment unit.

Caution:
With double VANOS adjustment unit removed:
Do not crank engine.
The toothed shaft on the inlet side might displace and slip out of the spline teeth; the inlet camshaft would no longer be non-positively connected and the valves could touch the piston.

Installation:
Installation of double VANOS adjustment unit is described separately from removal.
The assembly sequence for removal and installation is different.





Check dowel sleeves (1) for damage and correct installation position.
Keep sealing faces clean and free of oil. Apply a thin and even coat of sealing compound Drei Bond 1209 to contact surface edges of separating face between cylinder head and double VANOS adjustment unit.
Replace seal.





Install and secure double VANOS adjustment unit.





Reconnect plug connections to camshaft sensor and solenoid valves on exhaust and inlet sides.





Caution: Left-hand threads.

Insert and tighten down setscrews for hydraulic piston in toothed shaft on inlet and exhaust sides.
Tightening torque, refer to Specifications, Mechanical.





Replace sealing caps and install with special tool 11 6 170 or with commercially available short flat nose pliers.





Insert and secure seal plugs with new sealing rings.
Tightening torque, refer to Specifications, Mechanical.





Fit suspension lug.

Note:
If the double VANOS adjustment unit has been replaced, you must check and, if necessary, adjust the camshaft timing.
If work has been carried out which has "no" effect on the timing and it is assured that the timing adjustment is correct, the timing check described in the following does "not" have to be conducted.





Caution: Cylinder for chain tensioning piston is under spring pressure.

Remove cylinder for chain tensioning piston.





Insert special tool 11 4 220 in cylinder head and bring adjustment screw into contact with tensioning rail.





Preload tensioning rail with special tool 11 4 220 by rotating adjusting screw with special tool 00 9 250 or standard torque wrench to 0.7 Nm.





Pull special tool 11 2 300 back until flywheel is no longer secured in position.





Remove special tool 11 3 240.





Caution: Cover double VANOS adjustment unit; when the compressed air supply is connected, several drops of oil are sprayed out of the bore.





Connect compressed air (2 to 8 bar).





With compressed air supply connected, crank engine twice in direction of rotation until cam tips on inlet and exhaust camshafts on 1st cylinder face each other.





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.





Check camshaft setting: Fit special tool 11 3 240 to camshafts.





Note:
Due to the rubberized chain wheel, tolerances in the VANOS adjustment unit and running clearances in the splines, special tool 11 3 240 can protrude up to 1 mm above the inlet side in spite of the camshafts being correctly set.
If special tool 11 3 240 protrudes above the exhaust side, it will be necessary to readjust the timing.
If necessary, adjust camshaft timing.





Detach compressed air connection.
Remove special tool 11 3 450.





Fit oil pressure line with new seals.
Tightening torque, refer to Specifications, Mechanical.





Relieve tension on special tool 11 4 220 and remove.





Install cylinder for chain tensioning piston.





Remove special tool 11 3 240.





Remove special tool 11 2 300.
Assemble engine.