Either a combustion chamber, an oil vein, or both. Check for white smoke out the tail pipe for a combustion chamber leak and if the oil on the dipstick looks like chocolate milk it's contaminated with coolant.
Blown head gasket and/or cracked head.
Blown head gasket
Coolant leaking into any cylinder is a clear indication that the head gasket has blown.
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.
most likely a blown head gasket, cracked head, or bad intake gasket. with the s series. i would venture to say blown head gasket.
Yes it can, unless there is a small leak somewhere else.
No, only a blown head gasket or cracked head will cause coolant to mix with the oil. A leaking valve cover gasket will only cause oil to leak onto the engine block externally.
Head or head gasket leak
Signs of a blown head gasket are: White smoke that has a sweet smell coming from the exhaust. Loosing coolant with no apparent leak. Coolant mixed with the oil, which will look milky. Air bubbles in the radiator when the engine is started cold with the radiator cap removed. A cooling system bleed down test will verify a blown gasket or leak. Finally a compression test will verify a blown gasket or cracked head.
Are you asking why is your coolant disappearing? If so, it can be a number of things. A blown head gasket, leaking water pump, radiator, heater core, hose, to name a few. If you can see no apparent leak after driving the vehicle then suspect a blown head gasket. As this can do serious damage to your engine, I suggest you have this fixed ASAP.
The coolant will normally leak into the oil or into the cylinder
If you mean it suddenly started loosing coolant, then look for a leak. If you see no leak then suspect a blown head gasket. Stop driving the car until you get this repaired. If you continue to drive a car with a blown head gasket you will destroy the engine.