Regarding your inquiry, after the vehicle is parked for a long time, the antifreeze in the engine circulation system will flow back to the lower part, and many holes will appear in the engine circulation system under the action of thermal expansion and cold contraction. When the engine is started, the water pump begins to circulate antifreeze, especially when the thermostat is not opened, there is some air in the small circulation channel, which will lead to snoring. This is normal, as long as antifreeze is not lacking, there is no problem.