| 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 direct shift gearbox: remove noise insulation, 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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