Timing Belt: Service and Repair
Toothed belt, removing and installing
Note:
Mark the direction of rotation before removing the toothed belt. If a used belt rotates in the wrong direction when reinstalled, this can result in breakage.
1 - Engine support
2 - 45 Nm
3 - Toothed belt guard, top
^ To remove belt guard, it may be necessary to unbolt retainer for coolant return line (for turbocharger).
4 - Toothed belt
^ Mark direction of rotation before removing
^ Check for wear
^ Do not kink
5 - Idler roller
6 - 27 Nm
7 - 65 Nm
^ Use counter-hold 3036 to loosen and tighten
8 - Camshaft sprocket
^ For exhaust camshaft
^ Note installation position: camshaft sprocket is installed with smaller side facing out and TDC marking for cylinder 1 visible
9 - Tensioner
10 - Washer
11 - Tensioner for toothed belt
12 - O-ring
^ Replace
^ Lightly coat with coolant G 012 A8 D before installing
13 - Coolant pump
14 - 15 Nm
15 - Crankshaft sprocket
^ Contact surface between sprocket and crankshaft must be free of oil
^ Can only be installed in one position
16 - 90 Nm + 1/4 turn (90 degrees) further
^ Replace
^ Counter-hold with 3099 retainer to loosen and tighten
^ Place 2 washers between sprocket and retainer when mounting retainer
17 - 15 Nm
18 - 20 Nm
19 - Toothed belt guard, center
20 - Toothed belt guard, bottom
21 - 10 Nm
^ Removing toothed belt
Special tools, testers and workshop equipment required:
^ 10-222A Engine support bridge
^ 10-222A/1 Bracket for engine
^ Engine in vehicle
- Disconnect air duct at bottom of right-hand longitudinal member (air duct leads to charge air cooler).
- Remove sound insulation panels in center and on right (arrows).
- Remove ribbed belt and tensioning element.
- Remove coolant expansion tank and power steering reservoir (arrows) and move to one side with hoses connected.
- Disconnect vacuum hose from EVAP canister and from connection on throttle valve.
- Disconnect electrical connectors on coolant expansion tank and EVAP canister.
- Remove toothed belt guard (top).
- Set up engine support bracket 10-222 A with supports 10-222 A/1.
- Install retainer 3180 to right lifting eye and attach to engine support bracket 10-222 A.
- Lift engine slightly with spindle of engine support bracket 10-222 A.
Note:
Lift coolant expansion tank and power steering reservoir and tie them in place on the engine support bracket.
- Set crankshaft to markings for TDC of No. 1 cylinder (arrows) by turning central bolt on crankshaft sprocket in direction of rotation.
- Remove vibration damper, making sure not to change TDC position.
- Remove center and bottom sections of toothed belt guard.
- Unbolt engine support from engine console and engine console from body (arrows).
- Unbolt connecting piece between engine console and body.
- Take out engine console.
- Remove bolts for engine support (arrows), but do not take out engine support.
Note:
To remove the bolts for the engine support, raise or lower the engine slightly as necessary via the spindles on engine support bracket 10-222A.
- Mark direction of rotation of toothed belt with chalk or felt pen.
- Screw M5 x 55 stud -1- into toothed belt tensioning element. Screw hex nut -2- onto stud -1- using a large washer -3-.
- Only tension piston of tensioning element as far as necessary to secure it with a locking pin (e.g. from lifting appliance 2024A) arrow-.
- Pull out toothed belt through space between engine support and cylinder block.
- Installing toothed belt (setting camshaft timing)
Note:
^ The position of the toothed belt must be set as described below, even after repairs in which the belt is only taken off the camshaft sprocket.
^ When turning the camshaft the crankshaft must not be at TDC (danger of damage valves/piston crown).
- Align camshaft sprocket mark with marking on cylinder head cover.
- Place toothed belt on crankshaft sprocket (mark direction of rotation using chalk or paint).
- Install toothed belt guard, lower part.
- Install vibration damper (note installation position: hole in vibration damper is over projection on toothed belt sprocket).
- Align vibration damper marking with marking on lower part of toothed belt guard.
- Install toothed belt onto coolant pump, then tensioning roller, and finally camshaft sprocket.
- Pull out locking pin (arrow) and loosen piston of toothed belt tensioning element.
- Remove stud -1-.
- Turn crankshaft two complete turns in engine direction of rotation, set again to TDC and check adjustment.
- Install engine support and console.
- Remove engine support bracket 10-222 A with retainer 3180.
- Install toothed belt guard (center and top sections).
- Install ribbed belt and tensioning element.
- Install and secure coolant expansion tank and power assisted steering reservoir.
Tightening torques
