You can go to any parts house and for about $5.00 you can buy a tester. It is simple to operate.
Pressure test the cooling system Monitor antifreeze level
Typically a 50/50 mix of clean water and antifreeze will protect down to -34 degrees. Have your local auto parts store test your antifreeze.
You have a blown head gasket. Check the oil and antifreeze, they may have mixed. Have a mechanic pressure test your cooling system.
Pressure test system t determine where leak originates
Odds are you have blown a head gasket and the antifreeze and oil flow share the same gasket. As the gasket wears, the antifreeze mixes into the oil and vice versa! I suggest replacing your current antifreeze and do a full flush. Test it for a few days and test if you have oil again. A tell tell sign of a blown head gasket is black smoke (burning oil) or white smoke (burning antifreeze ) coming out the exhaust.
By Taste. Just kidding use an auto antifreeze tester
get a coolant system pressure test, there may be a leak in the heater core.
You may have a blown head gasket. Have a compression test and cooling system pressure test run.
Pressure test system to determine where leak orginates to determine fix
Call Around; Find A Radiator Shop or A Mechanic That Can Pressure Test Your Radiator. This Should Help
Blown head gasket.
Pressure test system to observe leak