What are the causes of Volkswagen sagitar valve ringing?

The reason why Volkswagen sagitar valve rings is as follows: 1. It is caused by the clearance between hydraulic valve tappet and cam (or valve seat). Most of the clearance is due to the excessive wear of the hydraulic tappet, and the abnormal sound caused by the rapid pressure relief of the oil pressure inside the tappet needs to be replaced. 2. Check the engine oil level for abnormal noise caused by too high or too low crankcase oil level. Abnormal sound caused by unclean chromatographic column needs to be cleaned; 3. For the abnormal noise caused by the abrasion of the valve guide, it is necessary to fix the valve guide and install the valve with thickened valve stem. Abnormal sound caused by too thin engine oil needs to be replaced with engine oil with appropriate viscosity; 4. For abnormal noise caused by low oil pressure, check the reason of low oil pressure.