It means your ball float valve inside the cistern either needs adjustment or replacing
It means that the tube is clogged. You need to clean it out or eventually you will have a leak of the water that is backing up in the system.
That device is called the refill tube. This allows water to go down the overflow tube to refill the water closet bowl while the tank is filling.
no it has a vent if it is coming out the vent it is over full.
if your water/antifreeze gets to hot it pushes out the over flow tube into the overflow container, as it cools down it will suck it out of the overflow and back into the radiator.
radiator cap might be leaking
It is important to keep fluids from leaking from a car. Excessive transmission fluid would be coming out of the overflow because there is too much fluid in the transmission, or because the seal has become worn.
Replace the pressure relief valve.
An overflow is a box that hangs on the back of the tank (or is sometimes built in) and allows the water to "overflow" to a wet/dry filter (the tank sized filters people have underneath their tanks). The overflow has a U shaped tube that allows water to siphon from the main tank into the overflow box. The overflow box then drains the water down a tube to the wet/dry filter continuing the siphon by pulling the water as it drains. If you are going to purchase on, they should come with instructions. www.wetwebmedia.com is a good place to learn about all types of fish related things.
This is gaseous water.
Is the small tube from the inlet to the overflow tube in place? Sometimes the gasket in the top of the fill valve will go bad and let it spray out of the top.
your water pressure/volume is to much for the overflow to handle.after repair try to turn shut off valve under toilet to slow water fill in tank.test by holding down float while refilling toilet.
The overflow tube is clogged is my first guess, unless someone or something has cracked the drain tube with activity in the area.