Haeter core
#2
I got a roll of heater hose from my local advance and hooked it to the heater core. I dumped an entire container of CLR in the heater core and left in in for about 20 minutes. Then I took one end of the hose and put it in a bucket and the other end to a water hose and ran water through it. The water that came out of the core was black. Now my heat works great.