take radiator out, it aint to difficult, and you will be able to get broken bit out (give us a shout if stuck). It is best to drain block through block drain bolt, as even if you flush water down expansion tank to bottom hose, you wont be flushing whole system. Fatherted, funny you mention it, as I did the very same thing with my matrix, but it kept coming out clear, which I know is good, but was kinda dissapointing as hoped to be actually clearing something