I have a 1989 Honda civic with 270,000km, the water pump is broken so i have to constantly top the radiator up. In the mornings there is white smoke for the first 5-10 minutes, and sometimes there are bubbles on the radiator however ive been told it can be due to low pressure, the car runs perfectly fine and this has happened for a while, as well the oil is rather dark. Could there be anything wrong?