i replaced my heater core due to puddle in passenger side floor, filled the radiator and over flow drove it a couple times had refill the overflow took it out to another car show got there and noticed the overflow was empty again got home filled it again turned the car on heat on high no smell no window fogging looked under the hood no leaks and did not notice anything from the exhaust could it be it just needed to fill the heater core and the lines thanks

 

Could have had some air still in the system that burped out. Keep an eye on it until it stabilizes.

 

ok thanks