UK CopperCore!!, Old Vauxhall Cavaliers have a good copper heater core in them. trouble is with scrap heater cores is the crap(TM) that's always inside them
, no matter how much you flush them there's always
more of the crap inside!
...
And stuff like RadFlush requires you to run the water through at car running temp (90-100DecC??) for half an hour or so...
NE1 know of some good stuff you can just put in to soak?. Caustic Soda maybe?...