Q: Coolant/antifreeze fluid leak

If you are not seeing a leak in the cooling system that usually means the coolant is getting in the engine. I would check your oil dipstick and look for a muddy milky buildup on the tip of the dipstick. This is a sure sign that you have a blown head gasket. A head gasket will blow out when the engine overheats and warps the head causing water to blow past the head gasket water jackets and get into the cylinder or oil passages in the motor. You will notice a milky substance inside the engine and you may notice a white smoke coming out the tailpipe that will have a distinctive odor. I would recommend having a technician come out and determine if this is the case and inspect for coolant leaking somewhere that you may not be able to see.