what happens to the crud that gets scraped off? is there loads? where does it go?

think u just pick it out :rolleyes:. i may just remove the whoel thing, scrub the day lights out of it and then refit with some coolant
 
Had this today. Just turned the ignition off. then on. did it again. so turn ignition off then on.. and it stoped :)

I work in IT so turn it off and on is all i know.