As important as it is to flush the cooling system you must also check the air side of the radiator. Debris passes though the condenser coil and plugs up the fins of the radiator and you can't see it easily unless you take the cooing package apart. To properly flush the system you need to do it in pieces, ie, just the motor, just the heater core and just the radiator. On the motor you have to remove the thermostat to do it right (don't forget to put one back!). It is a lot of work. Many gas stations now have a special rig that recirculates cleaning fluid to flush the cooing system. You may want to let them do it.Years ago when I had to power flush the coolant system I went to hardware store and got some PVC plumbing pipe and glue and made a garden hose adapter to clamp on to the disconnected coolant hose and reverse flushed it. I put the exit hose in a bucket to see what would come out. There was some bits and pieces in the flush. Do the chargecooler lines too. it will blow small chunks too. If you got a metal header tank CLR the rust out of it when disconnected from the system and rinse well before hooking it up.
Why are you going to take off the front bumper?
David Teitelbaum