| Checking hydraulic tappets |
| Special tools and workshop equipment required |
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| The hydraulic tappets that are pressed into the roller rocker fingers cannot be serviced. |
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| Irregular valve noises when starting engine are normal. |
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| Start engine and let it run until the radiator fan has switched on once. |
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| Increase engine speed to approx. 2500 rpm for 2 minutes (perform road test if necessary). |
Note | If the irregular valve noise stops but repeatedly re-occurs when driving short distances, then the oil retention valve is defective. Fitting location: in oil filter bracket → Item. The oil retention valve cannot be renewed separately. |
| If the hydraulic tappets are still noisy, locate defective tappet as follows: |
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| Rotate crankshaft until cam of hydraulic tappet to be checked faces upwards. Procedure on |
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| Vehicles with manual gearbox: push vehicle forwards with 4th gear engaged and ignition switched off. |
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| Vehicles with multitronic gearbox: remove noise insulation, remove torque reaction support and stop for torque reaction support, lever off cover cap from vibration damper and rotate crankshaft in clockwise direction via central bolt for vibration damper. |
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| Determine clearance between cam and roller rocker finger. |
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