Variable Valve Timing Actuator: Service and Repair
11 36 010 Removing and Installing or Replacing Double VANOS Adjustment Unit (M52TU / M54 / M56)
special tools required
- 00 9 250
- 11 2 300
- 11 3 240
- 11 3 450
- 11 2 220
- 11 6 170
Necessary Preliminary Tasks:
- Remove intake filter housing with air-mass flow sensor.
- Remove fan impeller with fan clutch and fan cowl
- Remove cylinder head cover
- 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.
Important!:
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, rotate engine at least two revolutions in direction of rotation until cam tips on inlet and exhaust camshafts on 1st cylinder face one another.
Pull dust guard out of the special tool bore.
Secure crankshaft in firing TDC position with special tool 11 2 300.
Important: Remove special tool 11 2 300 before starting engine.
Automatic transmissions only:
Illustration does not show automatic transmission
Important!:
Unscrew studs.
Locate camshafts with special tool 11 3 240.
Disconnect 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 the 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 conventional 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:
^ The engine must not be rotated while the double VANOS adjustment unit is removed.
^ The splined shaft on the inlet side can move and slip out of the splines, this could result in the inlet camshaft losing its non-positive connection and the valves resting against the piston.
Installation:
Installation of double VANOS adjustment unit is described separately from removal.
The assembly sequence for removal an, installation is different.
Note dowel sleeves (1).
Keep sealing faces clean and free of oil. Apply a thin and even coat of sealing compound Drei Bond 1209 (or equivalent) 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 Engine, Specifications, Mechanical.
Replace sealing caps and install with special tool 11 6 170 or with conventional short flat nose pliers.
Insert and secure seal plugs with new sealing rings.
Tightening Torque, refer to Engine, 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 turning adjusting screw with 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; some drops of oil are sprayed out of bore when compressed air is connected.
Connect compressed air (2 to 8 bar).
With compressed air supply connected, rotate engine twice in direction of rotation until cam tips on inlet and exhaust camshafts on 1st cylinder face one another again.
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: Place special tool 11 3 240 on 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, refer to Adjustments.
Disconnect compressed air connection.
Remove special tool 11 3 450.
Fit oil pressure line with new seals.
Tightening Torque, refer to Engine, Specifications, Mechanical.
Relieve tension on special tool 11 4 220 and remove.
Install cylinder for chain tensioning piston, refer to Timing Components, Timing Chain Tensioner, Service and Repair.
Remove special tool 11 3 240.
Remove special tool 11 2 300.
Assemble engine.