Aluminum radiator rust

[RPSil13]

is this rust in my radiator??
i drained the coolant and it all came out clean until the very end, it came out a little murky, could this have been caused by galvinazation, i checked the rubber mount and they all had rubber, no metal contact

 

[gaboonviper85]

That's rust from your engine block....flush the coolant system and install a coolant filter and that will help prevent deposit buildup like that.