have 2001 blzer that wasn't heating well and at idle would blow cold air. so i put my hand [use caution] on heater hoses by fire wall one [3/4 side] was hot, theother side[5/8]luke warm. after a little struggle got the hoses of at fire wall. i thenwent to parts store got 5 feet of 3/4" hose and 5 feet of 5/8" heater hose 3/4 is on passenger side. i hooked those up to the fire wall, then hooked garden hose up with sprayer that fit in both hoses and flushed each one about 4 times for maybe 30 seconds at a time. the 5' of hose gets the water out the engine compartment, and when your hooking garden hose up you dont get water in engine compartment. not sure this way is reccomended but i now have great heat and didnt want to put the dirt from heater core into rest of cooling system.

 

That is a very good way to flush the core out and keep everything nice and clean. I typically will pull the heater core hoses off of the engine and splice on another length of hose from there.

Nice successful repair job! Thanks for sharing!!