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Removing and installing toothed belt - vehicles with large engine support > < Toothed belt drive - exploded view
Removing and installing toothed belt - vehicles with small engine support
Removing and installing toothed belt - vehicles with small engine support
  Note
   
The engine support has to be removed in order to remove the toothed belt on vehicles with small engine support -1-.
  A13-10363
Special tools and workshop equipment required
t  Support bracket -10 - 222 A-
t  Diesel injection pump locking pin -3359- (2x)
t  Spring type clip pliers -VAS 5024 A-
t  Pin wrench -T10020-
t  Crankshaft stop -T10050- for engines with circular crankshaft sprocket
t  Locking pin -T10060 A-

   
t  Crankshaft stop -T10100- for engines with oval crankshaft sprocket
t  Locking pin -T10115-
t  Counterhold tool -T10172-
t  Locking fluid → Electronic parts catalogue
t  Safety goggles
t  Protective gloves

   
Removing
Engine cover panel (version 1):
–  Pull dipstick -1- out of guide tube.
–  Lift engine cover panel at sides -arrows 2- and pull off towards front -arrow 3-.
–  Re-insert dipstick in guide tube.
  A10-1664
Engine cover panel (version 2):
–  Lift off engine cover panel (outside -1- and inside -2-) by pulling up evenly.
  A10-10366
All vehicles (continued):
  Caution
Rules for cleanliness when working on the injection system → Chapter.
  WARNING
t  In extreme cases the fuel lines and the fuel can reach a temperature of 100 °C on vehicles with unit injector engine. Allow the fuel to cool down before disconnecting the lines - danger of scalding.
t  Wear protective gloves.
t  Wear safety goggles.
–  Disconnect fuel supply pipe -2- and fuel return pipe -1- by pulling release tabs.
  A20-1118
–  Disconnect fuel supply pipe -2- and fuel return pipe -1- from fuel lines.
  A10-1684
Fuel filter - version 1:
–  Pull fuel filter with hoses attached upwards out of the bracket -arrow-.
  A10-1685
Fuel filter - version 2:
–  Slacken bolt -1- one turn.
–  Remove bolt -2- and nut -3-.
–  Remove fuel filter with hoses attached.
  A20-10245
All vehicles (continued):
–  Unscrew bracket -3- for fuel filter.
–  Unscrew bolt at filler neck -2- for washer fluid reservoir.
–  Unscrew coolant expansion tank -1- and move clear to one side with the lines attached.
  Note
  A13-0646
Before removing, mark direction of rotation of poly V-belt with chalk or felt-tipped pen. If the belt runs in the opposite direction when it is refitted, this can cause breakage.
–  Turn the tensioner in the direction of the -arrow- to slacken the poly V-belt.
  A13-0083
–  Lock poly V-belt tensioner using locking pin -T10060 A-.
–  Remove poly V-belt.
  N13-10135
–  Remove tensioner for poly V-belt -arrows-.
  A13-0667
–  Remove top toothed belt cover by releasing retaining clips -arrows-.
  A13-0665
–  Pull cover off air duct (release clips on sides) -arrows-.
  A10-10367
–  Unclip air duct at the bottom by releasing clips -arrows-.
–  Detach air duct (bottom) together with air hose.
  A10-10368
–  Unplug electrical connector -1- at air mass meter -G70-.
–  Detach vent hose -3- and air hose -2-.
–  Unscrew bolt -4- and remove air cleaner housing.
  A10-10369
–  Remove bolts -1- and -3-.
–  Move vacuum hoses at rear intake pipe clear to one side.
–  Disconnect hose -2- for crankcase breather system at air pipe.
–  Release spring clip -4- with spring clip pliers -VAS 5024 A- and detach air pipe at connection for turbocharger.
  Note
Shown from rear with engine removed for illustration purposes.
  A21-0303
–  Set up support bracket -10 - 222 A- with adapters -10 - 222 A /3- on wing panel flanges.
–  Attach hooks of spindles to lifting eyes.
–  Take up weight of engine evenly with both spindles (but do not raise engine).
  A10-1686
–  Remove bolts -1- and -2- and detach connecting bracket.
–  Remove bolts -3 ... 6- and remove engine mounting.
  A13-0647
–  Remove centre noise insulation -fasteners 1 ... 3-.
  A10-1565
–  Remove noise insulation (left and right) -fasteners 1 ... 3-.
–  Unbolt drive shafts (left and right) from gearbox flange and centre bearing.
–  Detach drive shaft (left-side) from gearbox flange and tie up.
–  Remove front exhaust pipe → Chapter.
  A10-1566
–  Unplug electrical connector -2- at charge pressure sender -G31-/intake air temperature sender -G42-.
–  Remove bolt -4-.
–  Remove front air pipe with air hose by lifting retaining clips slightly -1- and -3-.
  A10-1665
–  Unscrew bolts -1 ... 3- and remove pendulum support.
  A10-1578
–  Remove bolts -1- and -2-.
–  Remove air pipe (right-side) by lifting retaining clips -arrows- slightly.
  A10-1679
–  Detach air intake hose from turbocharger by lifting retaining clip -arrow- slightly.
  A21-0304
–  Remove cover cap for vibration damper.
–  Unbolt vibration damper; counterhold on centre bolt with ring spanner.
  A13-0356
–  Unbolt toothed belt covers (bottom and centre) -arrows-.
  A13-0171
–  Remove bolts -1 ... 3- for engine support.
  Note
To remove the bolts for the engine support, raise or lower the engine slightly as necessary via the spindles on support bracket -10 - 222 A-.
–  Raise engine/gearbox assembly slightly with spindles and remove engine support.
  A13-0666
  Caution
The engine must only be turned at the crankshaft, in the direction of normal engine rotation (clockwise).
–  Turn the crankshaft to TDC for cylinder No. 1.
  Note
At TDC position the toothed segments -arrows- face upwards.
–  Lock hubs with locking pins -3359-.
  A13-0690
–  Lock crankshaft sprocket using crankshaft stop -T10050- for engines with circular crankshaft sprocket, or crankshaft stop -T10100- for engines with oval crankshaft sprocket.
l  The markings on the toothed belt sprocket and the crankshaft stop must align -arrow-. The pin of the crankshaft stop must engage in the aperture in the sealing flange.
  Note
The crankshaft stop can only be pushed onto the sprocket from the front face of the teeth.
  N15-10159
–  Mark direction of rotation of toothed belt with chalk or felt pen.
–  Loosen the bolts -arrows- for camshaft sprockets approx. 2 turns.
  A13-0674
–  Loosen securing nut -1- for tensioning roller.
–  Turn eccentric adjuster of tensioning roller anti-clockwise using pin wrench -T10020- until tensioning roller can be secured with locking pin -T10115-.
  A13-0675
–  Now turn eccentric adjuster of tensioning roller clockwise until stop and tighten securing nut -1- hand-tight.
–  Take off toothed belt first from coolant pump and then from the remaining sprockets.
Installing (adjusting valve timing)
l  Camshafts locked with locking pin -3359- (2x).
l  Crankshaft is locked using crankshaft stop -T10050- for engines with circular crankshaft sprocket, or crankshaft stop -T10100- for engines with oval crankshaft sprocket.
l  Tensioning roller locked with locking pin -T10115- and secured at right stop with securing nut.
  Note
t  Toothed belt adjustment must always be performed when the engine is cold.
t  The crankshaft must not be at TDC at any cylinder when the camshaft is turned. Otherwise, there is a risk of damage to valves and piston crowns.
  A13-0676
–  Ensure that tensioning roller is seated properly in rear toothed belt cover -arrow-.
  A13-0053
–  Screw in bolts -arrows-, but do not tighten.
l  It should just be possible to turn the camshaft sprockets on the hubs without axial movement.
–  Turn the camshaft sprockets in their elongated holes clockwise until the stop.
–  Fit the toothed belt to crankshaft, tensioning roller, camshaft sprockets, idler roller and finally to sprocket for coolant pump.
  A13-0674
–  Adjust toothed belt tension as follows:
–  Remove locking pin -T10115-.
–  Loosen securing nut -1- for tensioning roller.
–  Turn eccentric adjuster of tensioning roller clockwise using pin wrench -T10020- until lug -2- aligns with the centre of the slot on the base plate.
  Note
Make sure that the securing nut -1- on the tensioning roller does not turn at the same time.
–  Hold tensioning roller in this position and tighten securing nut -1- on tensioning roller to 20 Nm + 45° (1/8 turn).
  Note
  A13-0677
When tightening the securing nut, the pointer -arrow- may move up to 5 mm (maximum) to the right of the slot in the base plate. This position must not be corrected, because the toothed belt stretches slightly when running in.
  N15-10038
–  Attach counter-hold tool -T10172- as shown in illustration and apply tension to driving section of toothed belt by pressing in direction of -arrow-.
–  Tighten camshaft sprocket securing bolts -arrows- to 25 Nm.
–  Remove locking pins and crankshaft stop.
  N15-10016
Checking valve timing:
  Caution
The engine must only be turned at the crankshaft, in the direction of normal engine rotation (clockwise).
–  Turn crankshaft two rotations in normal direction of rotation until the crankshaft is just before TDC again.
–  Lock the hub -A- into place with the locking pin -3359- when turning.
–  Check whether:
t  The hub -B- can be locked with the locking pin -3359-;
t  The crankshaft can be locked with the crankshaft stop.
t  The tensioner pointer is centred or a maximum of 5 mm to the right of the slot in the base plate.
  N15-0702
Adjusting the valve timing:
If hub -B- cannot be locked:
–  Loosen securing bolts -2- for inlet camshaft sprocket.
–  Place a ring spanner on the centre bolt for inlet camshaft.
–  Turn hub until locking pin -3359- can be inserted.
–  Tighten bolts -2- for inlet camshaft sprocket to 25 Nm.
–  Remove locking pins and crankshaft stop.
  Caution
The engine must only be turned at the crankshaft, in the direction of normal engine rotation (clockwise).
–  Turn crankshaft two rotations in normal direction of rotation until crankshaft is at TDC again.
–  Check valve timing once again → Anchor.
  N15-0702
If the crankshaft cannot be locked:
–  Loosen bolts -1- and -2- for the camshaft sprockets -A- and -B-.
–  Continue to turn the crankshaft in the normal direction of rotation until it can be locked with crankshaft stop -T10050- for engines with circular crankshaft sprocket, or crankshaft stop -T10100- for engines with oval crankshaft sprocket.
  Note
If the crankshaft has been rotated beyond TDC, turn it back slightly so you can then reset it to TDC by turning in the normal direction of rotation.
  N15-0702
–  Tighten bolts -1- and -2- for camshaft sprockets -A- and -B- to 25 Nm.
–  Remove locking pins and crankshaft stop.
  Caution
The engine must only be turned at the crankshaft, in the direction of normal engine rotation (clockwise).
–  Turn crankshaft two rotations in normal direction of rotation until crankshaft is at TDC again.
–  Check valve timing once again → Anchor.
Assembling:
Installation is carried out in the reverse order; note the following:
–  Install centre and bottom sections of toothed belt cover.
  Note
t  Renew seals and gaskets.
t  Secure all hose connections with the correct type of hose clips (same as original equipment) → Electronic parts catalogue.
–  Install engine support → Chapter.
–  Install vibration damper → Chapter.
–  Adjust assembly mountings → Chapter.
–  Install poly V-belt → Chapter.
–  Adhere to the instructions for installing air pipes and hoses with plug-in connectors → Chapter.
–  Install air pipes → Chapter.
Tightening torques
  N15-0702
ComponentNm
Tensioning roller for toothed belt to cylinder head20 + 45° 1)
Camshaft sprocket to hub25
Toothed belt cover (bottom) to cylinder block10 2)
Toothed belt cover (centre) to cylinder block10 2)
Engine mounting to body50
Connecting bracket to engine mounting/body20 + 90° 3)4)
Pendulum support to subframeManual gearbox → Rep. Gr.34, automatic gearbox → Rep. Gr.37
Tensioner for poly V-belt to bracket for ancillaries23
l  1) 45° = one eighth turn.
l  2) Apply locking fluid when installing; refer to → Electronic parts catalogue for locking fluid.
l  3) Renew bolts.
l  4) 90° = one quarter turn.

   

Removing and installing toothed belt - vehicles with large engine support > < Toothed belt drive - exploded view