Auto Air Conditioning & Heater Repair: 1994 Buick Century (2.2L) Heater/Coolant sytem problem, radiator fans, heater coil

Question
I flushed my cooling system using the prestone backflush kit and changed the thermostat.  I got a ton of rusty fluid out.  When it ran clear I put water and Prestone Super Cleaner into the system.  It ran well and didn't overheat.  I left it in for about 3 hours of driving per the instructions and then flushed the system again.  I got a lot of rust colored fluid out.  Then I put the recommended mixture and amount of antifreeze.  Now it overheats very quickly and even while idling.  I re-flushed the system again and placed more Prestone Super Cleaner in it.  Now it runs a little on the hot side but at least not in the red.  Why is this happening?  My heater still doesn't work but I don't care.  Both radiator fans are working.  The water pump seems to be working because I can see fluid circulating in the radiator while it is running.  Please help.  Thanks again.

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Followup To
Question -
About 2 months ago I noticed my heater stopped working.  It blows cool air.  My A/C works great..cold as ice.  Just the other day my engine temp light came on.  I immediately stopped and let it cool.  This car is old but only has 37k miles on it.  I have never changed the coolant and it looks rust colored. I acutally just bought the car from an old lady who never changed it. Also the coolant was low when the engine overheated so I added some (50/50 mix).  Now it seems that the engine runs on the hot side but still in acceptable range and gets to operating temperature quickly.  It is hotter if I'm just idling but if I rev the engine it cools some.  I think the heater coil is clogged/maybe even part of the engine block.  I don't see a leak.  If you agree then do you think that back flushing is sufficient to correct the problem?  Should I even try to do that?  My plan was to flush it and change the coolant.  If you disagree with this diagnosis then please let me know.  I really don't care if the heater works cause I live in a warm environment.  I just need this car to last one more year and I don't want the engine to overheat again.  Thanks in advance for your help.  As stated in the title my car is a 1994 Buick Century with the 2.2L engine.
Answer -
YES, back flush the entire cooling system including the radiator, engine, hoses, and heater core and don't forget to flush out the over flow jug and when your done, Replace the thermostat and add 50/50 coolant.

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Answer
All the JUNK that was in the engine cooling chambers is now in the lower half of the radiator.

1. try flusing the system a few more times and if this does NOT improve the over heat problem I would if it was my vehicle, install a NEW radiator.


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