Execution order
1. Start and warm up the engine. Let it run until the fan turns on.
2. Maintain a rotation speed of about 2500 min⁻¹ for 2 minutes.
3. If noise is heard in the valve drive, then one or more tappets are faulty. To determine which tappet is faulty, remove the cylinder head cover and turn the crankshaft clockwise so that the tops of the camshaft lobes are directed upward from the hydraulic tappet being checked. Press the tappet with a wooden or plastic wedge and measure the tappet free travel with an indicator, which should be no more than 0.1 mm before the valve opens. If the tappet free travel exceeds the specified value, replace the tappet.
The text is based on materials from the website AudiManual