More than likely your freeze plug is going to be the culprit and I would suggest you look there first. On some vehicles, the freeze plug is covered by the transmission housing or just plain difficult to get to and inspect for the average person. On older models, the freeze plug can rust out and create a leak. In this case take it to your trusted mechanic for repair.
antifreeze does not enter the engine at any time. locate and follow your radiator hoses and follow then and check for cracks or punctures.
it is probably your freeze plugs
Look at the oil on the dipstick. If you have antifreeze leaking into the crankcase the oil will be milky.
Need to check the back to corners on the intake, they our none for leaking. There is 2 freeze plugs in the back of engine between the bell houseing and block.
you might have a blown head gasket and the coolant is leaking into the cylender and the engine is burning it.
Most likely cause is the intake manifold gasket-antifreeze will usually leak down the back of the engine and drip off of the starter or somewhere in that area.
Not knowing what year, make, model and engine you have I can only guess that you may have a rotted out welsh plug on the back of the engine block.
Usually a leaking hose into or out of the water pump (depending on its location), or the water pump gasket.
Possible leaking hoses or water pump
Either one of the heater hoses are leaking or you have a freeze plug on the side of the engine leaking.
look on the ground and follow it straight up to the engine
Most of the time it is because the water pump is going out and it is leaking where the pulley is on the engine.