What does it mean when your coolant reservoir is bubbling?
What does it mean when your coolant reservoir is bubbling? rising air pressure Bubbling indicates rising air pressure in the cooling system, which is a sign that the flow of liquid is blocked by a pocket of air. This escaped air causes bubbling in the coolant/antifreeze reservoir, which can often be mistaken for boiling. Why are there bubbles in the overflow tank? Problem Bubbles. Though it is completely normal to find bubbles in the overflow tank while the engine is not overheating, bubbles in the coolant could be the sign of a leak at the head gasket. To test for...