I had the same exact issue when i swapped mine. I ran dish sop through it fora bit to clean the debry out of te jackets. Then I used a vacum pump to fill the system. Basicly it installs on your radiator and youhook it to a Compressor it creats a vacum and you drop the hose in coolant and it sucks the coolant into the block. Its the only way i could get allof the air out of my new block. and i yet to get any heat. But it stopped overheating on me.