WATER MIXING WITH OIL

The vehicle is Sinotruck Howo truck, when the engine is hot, the vehicle starts normally but when the engine is cold, it will not start unless the engine is forcefully turned manually before it will start. However, after the engine was started, it was eventually noticed that the engine oil is mixed with water, after changing the cylinder head gasket, engine oil and oil filter, it is still mixing oil and water. I do not know how and from where the water is mixing with engine oil.