rush peterbilt bad motor okc, Oklahoma

i bought a used trk from peterbilt in march 2012 no warrenty,my fault, took the trk to my company to lease it on it would not pass inspection, bad slack ajusters and other things that should never have a problem passing insp, exspecialy when you buy from some one like rush peterbilt. anyway i took it back they took care of those problems. within the 1st wk i blew a botton radiator hose, no problem part of trking, well when the coolent was drained in order to fix the broblem, the coolent was a brown rust color, does that sound normal?? well i call the salesman that sold me the trk, he says should have bought a warrenty, i call corporate, to explain how unhappy i was about what i saw and how unpleasent, my 1st buying exp was.told him i was sold a trk that wouldnt pass insp,and it was not serviced (pm). nothing came of it. had trk in two pete houses and one cat house since march 2012 for lack of power, all three put the trk on a computer to chk the ecm ( the trucks brain) found no eletrical faults. 8/23/2012 trk brakes down on the side of the road,have it towed to a shop, and the trk needs a new motor after i put 70,000 miles on it, and i called that salesman atleast once a month for somthing with that trk since i had it, should have bought a warrenty he says,and peterbilt is looking the other way. they sold me a lemon!!!!!!