radiator coolant

[turbulence]

Why does my radiator coolant decreases and goes into my reservoir, what happened if my reservoir is full?

 

[traxxas-modifier]

there is air coming out from your bore going to radiator.
that bubbles of air will push the coolant from your radiator
to your reservoir.

its like this,
you zip a coke using a straw then suddenly you blow it...

compression leaking?