Coolent does not have to be "Milky" to have a leaking head gasket.
The exhaust could be leaking into the coolent and cause overheating. Check for bubbles in the radiator while the engine is running, with the radiator cap removed, and the coolent visible and flowing.
The exhaust could be leaking into the coolent and cause overheating. Check for bubbles in the radiator while the engine is running, with the radiator cap removed, and the coolent visible and flowing.
