Toothed belt, removing and installing
Special tools, testers and auxiliary items required
- Toothed Belt Tensioner T10020
- Locking Tool T40098
Removing
- Remove engine cover - arrows -.
CAUTION:
Cover cap of expansion tank with rag and open carefully, as hot steam or hot coolant may escape when opening.
- Open cap of coolant expansion tank.
- For vehicles with auxiliary heater, remove bolts - arrows - for exhaust pipe of parking heater/auxiliary heater on noise insulation.
- Loosen quick-release fasteners - 1 - and - 2 - and remove front noise insulation.
- Drain engine coolant → Cooling system, draining and filling
- Bring lock carrier into service position → Lock carrier, moving into service position .
- Disconnect coolant pipe - arrow -.
NOTE:
- Before removing ribbed belt, mark the turning direction on it with chalk or a felt tip pen. A reversed turning direction can cause damage to the belt under operating conditions.
- Mark direction of rotation of ribbed belt.
- Pivot belt tensioner for ribbed belt in direction of - arrow - to relieve tension on ribbed belt.
- Secure tensioning element using Locking Tool T40098.
- Remove ribbed belt.
- Bring camshaft gear to marking for TDC cylinder 1 by turning crankshaft. Marking on camshaft gear must align with arrow on toothed belt guard.
- Remove vibration damper/belt pulley.
- Remove bolts from lower toothed belt cover - arrows -.
- Remove remaining bolts from toothed belt guard - arrows - and remove toothed belt guard from engine.
- Mark rotational direction of toothed belt.
- Loosen tensioning roller and remove toothed belt.
- Then, turn crankshaft back slightly.
Installing
NOTE:
- When turning camshaft, crankshaft must not be at TDC. Valves and/or pistons may be damaged.
- The engine must be no more than warm to touch.
- Place toothed belt onto crankshaft sprocket (observe direction of rotation).
- Secure lower toothed belt cover with two lower bolts.
- Install vibration damper/belt pulley with new bolts.
- Set crankshaft and camshaft to TDC at cylinder 1 - arrows -.
- Route toothed belt in sequence: Tensioning roller, camshaft gear, coolant pump and last over relay pulley - arrow -.
NOTE:
- Be sure tensioning roller is properly seated in cylinder head.
- Tension toothed belt. Do this by turning hex key at eccentric toward right (in direction of - arrow -) until notch is positioned above tab.
- Release tension on toothed belt again.
- Now tension toothed belt until notch and tab align.
- Tighten tensioning roller nut.
- Turn crankshaft 2 revolutions further in direction of engine rotation until engine is positioned at TDC again. For this it is necessary that the last 45 ° (1 /8 rotation) is turned without interruption.
- Check tension of toothed belt again. Specified value: Tab and notch align.
- Check valve timing again.
If markings do not match:
- Repeat valve timing adjustment.
If markings match:
- Install toothed belt guard - arrows -.
- Install crankshaft belt pulley → Crankshaft belt pulley, removing and installing .
- Install ribbed belt → Ribbed belt, removing and installing .
- Fill with coolant → Cooling system, draining and filling .
- Install lock carrier with attachments →
- 50 BODY, FRONT
- 50 - BODY - FRONT for BODY EXTERIOR - CABRIOLET
- Place torque support stop onto rubber buffer for torque support under its own weight and tighten nuts - arrows -.
- Install front bumper cover →
- 63 BUMPER
- 63 - BUMPERS for BODY EXTERIOR - CABRIOLET
- Check headlight adjustment →
- 01 - MAINTENANCE
- 01 - MAINTENANCE for MAINTENANCE PROCEDURES - CABRIOLET
- Install noise insulation pan.
- Install engine cover.
Torque specifications
| Component | Nm | |
|---|---|---|
| Toothed belt tensioning roller to cylinder head | 23 | |
| Lower toothed belt cover to cylinder block | 10 3) | |
| Center toothed belt guard to cylinder block | 10 3) | |
| Vibration damper/belt pulley | 10 + 90 ° 1)2) | |
| Torque support stop | 28 | |
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