Pressure test system t determine where leak originates
yes if your vehicle over heats
crack the engine block and oil mixes with water or antifreeze.
First thing you should check is the antifreeze level. If that is fine, replace the thermostat. If it still over heats after the thermostat, then most likely you need to replace the waterpump. If your antifreeze is low, check for leaks, the radiator, hoses, heater core, and water pump. If the water pump is leaking, that is your problem, replace that and thermostat all in one.
smell of antifreeze and no visable leaks usually indicates that the heater core needs replacing
Same color as what?
Oil/antifreeze mix is usually caused by head gasket leaks or valve cover gasket leaks.
no
Find where it is running out and repair the cause.
Need to get a pressure tester for rad. Do not pump up over 10LBS. And then look at the rear corners of the intake real close for leaks. The vortec engines are none for intakes leaking antifreeze. BE SURE TO CHECK ENGINE OIL CLOSELY FOR ANTIFREEZE
possibly the water pump or a bad hose
heater core leaking
In the event that it over-heats and seizes, then yes. If your cooling fliud is plain water, and the engine hasn't frozen, then lack of antifreeze should not affect things in the short term. It is obviously desirable to have antifreeze in cold weather so the the enginge doesn't freeze. As above, if there is no cooling fluid at all, the engine will over-heat and sieze up.