The engine of the new car is ringing. Will it get smaller after the running-in period?

At present, the machining accuracy of vehicles is very good, and some engines have been tested before leaving the factory (that is, the engines are not driven by the energy generated by fuel combustion). The so-called running-in is an old calendar. As long as driving is not too violent, there is no problem.

As for dadada, you mean the chassis after parking. That's the sound of the exhaust pipe expanding with heat and contracting with cold.