Scottydoggs--
Probably due to some poor wording on my end but the entire system has been flushed out, multiple times, including the block and heater core. The rad caught the worst of the Dexcool though. I replaced the reserve tank and hoses more recently, along with another flush. Periodically (every couple weeks?) I pop the radiator cap and ensure it isn't re-gunking, and I haven't had any problem since.