Hey people my 323i over heated while idling for 20 mins and blew the expansion tank. I've replaced that and changed coolant but after checking car over while idling again I noticed the temp gauge hit top middle and stayed there okay but the radiator stayed cold top and bottom. The thin black pipe across the front got warm but the main rad was stone cold all over. The previous owner has put k seal in it as noticed the copper over spill on old expansion tank, could this have clogged the radiator. Also the fan never came on, I've tried turning the ac on full heat with the engine off but fan still didn't start. There is power going to the connector just wasn't sure how else to check it. Sorry it's a long rambling question.