Engine oil leakage can lead to expensive and extensive repairs as engine oil provide the protection for the engine . A car running with low or no engine oil leads to expensive repairs.
Milky engine oil usually indicate major engine problem . Engine oil turn milky because water or engine coolants leak into the engine oil. This usually means a blow head gasket A leak in the head gasket allow coolant to pass into the engine oil system. When coolant and oil mixed the result is a milky engine oil.
In rare cases , milky engine oil could be due to leak from the transmission cooler or collection of moisture created by combustion which builds up because it was not allowed to reach and maintain normal operating temperature.