well, i bought a radiator awhile back from indyparts on teamfc3s, (he usually has a good reputation, but I dont know what happened here)... and i finally went to install it tuesday....and before I hooked up all the hoses i was like, i should flush it out with the water hose......started doing that and all these chunks of yellow stuff and what looked like sand started coming out...is this rust? is this radiator no good? will a radiator flush product work for this problem? I really dont want to hook it up with all that **** inside of it

 

Pics?

 

rust is red... probably the hunks of yellow that you mention are either aluminum corroision or calcium build up from the last owner using non distilled water for the coolant.

 

i just removed my stock S5 radiator today b/c it busted a seam. When I got it out I tilted it to the side and like yellow colored liquid ran out of it..nasty crap. Also the top plastic arm on that connects to the water pump was all cracking and i could break pieces off with just a little pressure with a finger. New radiator comes next week wednesday.