Over in Poland we use anti freeze thats good down to minus 40 , and we put it in neat , no dilution...It might help to remove the plastic shroud that goes around the fan and directs the cold air towards the water pipes...I took mine off as it made it difficult to get at stuff , i don,t think it serves any real purpose as regards cooling , its just to stop you sticking your fingers in the fan...Since throwing mine away the tempreture has not increased at all...