Metal sound of tank 300 cold car starting

Hello, I would like to ask what is the reason for the metal sound of tank 300 cold car starting? The reason why the cold car of No.300 tank makes a metallic sound when it is started is:

1, 300 boxes of cold cars start, the water temperature and oil temperature are not high. Coupled with the lack of oil viscosity and lubrication, the top cylinder can not be adjusted, and there will be metal friction when the cold car starts.

2. The valve rocker arm is worn, resulting in excessive clearance or excessive carbon deposition in sludge, and the dirty throttle will also cause a metallic sound when the cold car starts. Tank 300 is the first "intelligent luxury off-road SUV" built by WEY brand based on the intelligent professional off-road platform of Great Wall Motor.