The answer you want to hear is that it is something cheap and simple like a bad coolant pressure cap. Could be this and it would be an easy thing to try.
But it could also be more complicated like a bad thermostat which would cause the engine to over heat and force coolant into the overflow reservoir. Not too bad to fix on most cars.
And what you really do not want to hear is that this is because you have a bad head gasket that is allowing combustion gases to pressurize the cooling system. Fixing the head gasket is a big job.
But it could also be more complicated like a bad thermostat which would cause the engine to over heat and force coolant into the overflow reservoir. Not too bad to fix on most cars.
And what you really do not want to hear is that this is because you have a bad head gasket that is allowing combustion gases to pressurize the cooling system. Fixing the head gasket is a big job.
