Lots of good suggestions for the flush, and the antifreeze in the proper proportion, will keep it running cool.....but you'll be doing yourself a favor if you spring $1.00 for a couple gallons of DISTILLED water. On a 50/50 system you'll be pleasantly surprised at what DOESN'T build up in your radiator.
Once you've got the system clean why not keep it clean? Hope this helps.
