Probably a blown head gasket. Get a technician to look at it. If it is, it will be a major ordeal.
Head gasket could be bad
It depends on if you see the antifreeze leaking or it is just disappearing. If it is just disappearing then a bad head gasket or cracked head may be the problem. The smoking could actually be vaporized antifreeze. If that is the case don't run it until you can get it fixed.
The headgasket has failed.
It could be caused by a defective pressure cap on the radiator cooling system.
there might be a leak some where in a coolant line. or maybe you have a leak in your radiator.
Defective water pump.
heatercore leaking! also change thermastat.
because you probaly changed it with the wrong water
Possibly head gasket.
Probably a blown head gasket. If the car has an (engine) oil cooler it might be a leak there too.
What joint exactly is leaking on you p-trap?
Seized belt driven accessory; i.e. alternator, a/c compressor, idler pulley, tensioner pulley, water pump, etc.