It can be. If you live in a cold area it could freeze. If you live in a hot area, it could boil.
On collant bottles, it will tell you not to use collant or water alone. It will tell you the proper mixtures to use.
Either the cap is bad, your tank is either cracked at the seam or it has a pin hole that you can't see and the coolant is vaporizing ( steam ).
There shouldn't be just water in the expansion tank. If the coolant (50% anti-freeze and water) appears to be boiling in the expansion tank, you may have a bad head gasket or cracked head.
The overflow tank for coolant will "boil" if there is air getting in the coolant chamber. This can be a head gasket going bad.
Low coolant, bad coolant tank cap, stuck thermostat, or clogged coolant line.
Check coolant level in recovery tank Perhaps a bad sensor. Sensor located in coolant recovery tank
Bad sensor? Should be located at the bottom of the coolant recovery tank
Coolant? Bad radiator Radiator has a separate cooling tank (usually at the side or bottom of radiator) for transmission fluid. At times this tank ruptures allowing coolant to get into transmission. Most times causing a transmission failure.
There is a coolant level sensor in the bottom of the coolant tank. If the tank has enough coolant, then the sensor is bad. You can buy a new tank for about $50 (Rockauto.com or Autozone) and replace it in an hour or so. Or just disconnect the cable from the sensor and check your coolant level on a regular basis.
If your car is leaking coolant get it fixed and put in the recomended coolant for your car. You should locate that info in the manual, also putting water in the winter is a bad idea since the water could freeze causing engine damage. I supposed you might be able to run it for a while in the summer with just water but get the leak fixed and put in the recomended antifreeze/coolant
ya who asked this?
this is not anweringf my question my question
When the water pump goes bad it can leak coolant. Coolant loss can also be caused by bad hoses, a bad radiator, or a hole in a freeze plug.