slant is running hot

ahhh, laugh if you will, i filled the cooling system with a mix of 50/50 purple power and water ran it withthe cap off let it get hot. of coarse it wa smaking a sudsy mess, i flushed it out and ran it again. nothing real significant came out, until i ran it up to temp at high idle. i flushed it out with just water and kept refilling and letting it get warm, draining the system once it got warm, the first few times, straight black funk came out. not even rust color. it was black. i blasted the heater core out again and it seems to be good now. i flushed it about 8 times. rad drains much faster now and the temp seems to be holding pretty low. we'll see.