Engine coolant temperature is cooled by the radiator, moved by a water pump and controlled by a thermostat.
If there are troubles with any of those components the coolant will boil
Also if the head gasket goes bad gasses from combustion inside the engine will get into the coolant and cause it to boil.
when your engine is hot it causes the water to boil and the water and the anti freeze will come out of the overflow pipe.
The overflow tank for coolant will "boil" if there is air getting in the coolant chamber. This can be a head gasket going bad.
The radiator cap could be the cause of coolant reservoir overflow or backup. Have the cap checked to see if it is bad.
THATS WHAT THE OVERFLOW/EXPANSION PACK IS FOR. WHEN ANTIFREEZE/COOLANT BEGIN TO BOIL IT EXPANDS AND IT NEEDS A PLACE TO GO. THERE FOR IT GOES IN TO THE OVERFLOW/EXPANSION PACK. THIS PREVENTS DAMAGE TO THE ENGINE/RADIATOR AND OVERHEATING. THERE IS ALSO THE POSIBILITY OF A MALFUNCTIONING SENDING UNIT/GAUGE.
Coolant is old.
I'm having to guess it's the low coolant light? Possible coolant switch in the overflow bottle is dirty or defective., Is it low on coolant? Possible wiring issue to sensor.
The overflow bottle may overflow if: 1. The car is overheating - this means after the coolant in the radiator gets heated up and expands it flows to the reserve bottle but the radiator doesn't cool down to suck back the coolant from the overflow bottle, but just keeps on sending coolant to the bottle. 2. You may have put excess coolant in the bottle - hence heated coolant from the radiator didn't get enough space.
Heat from the engine causes liquid to expand. It used to overflow onto the ground if it caused enough pressure to open the radiator cap. The overflow tanks were installed to automatically catch and return the coolant to the cooling system.
The engine coolant reservoir or the overflow bottle.
Either theres a clog. or clogged on your engine blog or on your hose.
The car is overheating. Possibly the thermostat is stuck closed. Have it checked by a mechanic.
no antifreese