Because some opening formed which is allowing coolant to leak out.
No it probably means you have a leak some where. Try pressurizing your system to find the leak.
It sounds like the tank has a leak.
Waterpump, hoses coolant reservoir are possibilities
Could be a bad water pump or a leak in the line
Sometimes the reservoir tank is broken, where the water pump is located. Im sorry, I was confussed with the winshield tank. But, the coolant reservoir tank sometimes leak in small holes in the base or near the cap.
If you're adding coolant to the reservoir often, you have a leak somewhere. Have the cooling system pressure tested. That may force the leak to show up.
Check the coolant reservior for any leak. 1. If there is leak, try to stop the leak by A). go for coolant reservior replacement from dealership or from junk yard used part dealer. B). Stop the leak by putting adequate glue (i.e. glue which could sustain high temp) over the leak area. 2. If there is NO leak, it is probably a bad sensor, a known problem according to the Mazda Parts Dept. Replace the reservoir which includes the coolant sensor. They are sold as one part.
There is air in the system, probably from a head gasket leak
Possibly a leak in the coolant reservoir bottle.
I'm thinking the coolant level in the reservoir is to high to begin with. The cooling system has to work harder when the ac is running. The coolant expands as it heats up. If the coolant level was high to start with it will push out the excess.
Well, you said it was leaking through a bolt by the coolant container. That is where the leak is. More than likely the reservoir is leaking.AnswerI had a 2000taurus that had a messed up reservoir leak right by a nub that held it in place. temporarily switched it out for a used one, that one cracked as well. had to buy a new one from ford costing about $60.00
The coolant level sensor in the coolant reservoir detects the coolant level is low. The coolant system must have a leak in it somewhere. Have a trusted mechanic diagnose it soon before you do damage to the engine.