Engine coolant constantly decreasing

Have you checked the radiator cap yet? you can loose a lot of coolant from a bad one and not always notice it on the ground. Also have you checked for a wet floor board inside the car. Have you checked for a bad head gasket?

Checked the cap, and for wet floor board, all is good. Have not checked the head gasket yet. If the head gasket is the problem, I guess the coolant is mixed with the oil or enters the combustion chamber, if so is it safe to travel with the car or drive it for a while as it will take some time to get my hands on a new head gasket. Thank you.

That would be coolant getting into the combustion chamber. I would not be making any long trips if that is what it is. Did you replace the radiator cap?

Yes, I have changed the cap. Could the coolant cause any damage in the chamber?

It could effect how well the cylinder gets lubricated.