You need a head gasket.
The coolant has oil in it. Possible causes are a failed headgasket, or a leaking oil cooler,
blown headgasket
If coolant isn't leaking externally then it has to be leaking internally. A leaking head gasket or cracked head may be the problem. If this is the case, as it gets worse more coolant will enter the combustion chamber or engine oil. Either way you will be able to determine as it gets worse. There will be white smoke from the exhaust. May be intermittent. This is if coolant is leaking into combustion chamber. If leaking into oil, you will notice that the engine oil will have a brown/milky look to it as you check the oil level on the engine oil dipstick.
It is possible for engine oil to float on engine coolant. This occurs when there is a leaking or blown gasket.
The head gasket sits between the head and the engine block if it is leaking out where you can see the coolant, yes you can smell the coolant if it is leaking into the engine no you cannot smell the coolant. You can check the oil to see if it has coolant in the oil if it does then the head gasket might be blown.
You should able to tell if it's leaking so I assume that you are not seeing any coolant where you park so it's a good chance you got a blown head gasket and the coolant is leaking in your cylinders and being burned off or leaking into your oil. Check your oil after running and if it is foamy it has coolant in it.
try taking out the thermostat and have you put to much oil and coolant in the radiator
head gasket is leaking into oil
Check the water pump. Examine it for traces of dried coolant that might be leaking out of the casting.
Coolant leaking into engine oil? Leaking head gasket Run engine to normal operating temperature pull oil dipstick and let a drop fall onto hot part of engine - oil will smoke coolant will sizzle
Head gasket could be leaking
Crystalized coolant? due to a leaking headgasket?