I am more sensitive to this problem because the compartment is large and needs heating.
My successful experience is to take over the small circulation separately, connect the highest point of warm air
(higher than the engine), install a water tank cover (running air), and directly close the large circulation with a hand valve so that the water temperature can come up.
Analysis:
Thermostat. It can be found that when the temperature is 4-5 degrees
, the antifreeze with a temperature of -3 degrees in the water tank flows into the cylinder
. Although the amount is small, it is one of the reasons for the diesel engine whose water temperature is lower than that of gasoline.
The thermostat has an eye to escape because the small cycle is closed.
I believe this is also one of the reasons.
Why can the temperature be raised by closing the large cycle with a valve?