How does the coolant in the resivour enter the system
Its pulled in by vacuum.
Coolant is like anything else, when it gets hot, it expands. This forces coolant out of the radiator, through the little hose that connects to the plastic reservoir, and into the reservoir. When the coolant cools down it contracts, pulling coolant back into the radiator. This is why it's very important to have the radiator filled to the tippy tippy top when the engine is cold. Like from sitting overnight. HTH. -Jim
through the little rubber hose-
The reservoir should never be empty. There is a cold level line and a hot level line. Do as Jim said and fill the radiator to the top when cold and then add fluid to the reservoir cold line.
Looking for a Used G6 in your area?
CarGurus has 4,956 nationwide G6 listings starting at $1,500.
Search Pontiac G6 Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Pontiac G6 Experts