On my friends astra convertible G (1. the water coolant light on the dash flashes off and back on every 10 seconds or so. The water in the water tank was very look the other day so they topped it up with just normal tap water, disconnected the plug, wiped it clean and then plugged it back in. The water was pumping into and out of the water tank like it is ment to and the light went away. Few days after the light came back on again, Flashing every 10 seconds or so again, the water leave in the tank hasnt dropped at all so i dont know why this is happening
Anyone know of anything i could check for her or try before taking the car to a garage to look over it? I have been told to empty the whole cooling system and put in fresh coolant and see if that works but want to check everything out 1st if possible!