I dont do a lot of mileage in my car normally about 100 miles a week around town, i take it easy not thrashing it and always get steam on tickover, even at working temp, so i decided to give it a bit of a clear out by flooring it up a quiet road, and all i can say is the amount of white smoke that came out of the exhaust was unbelievable, i have never seen so much it was like a huge smoke screen. i take it the exhaust must be saturated with water....