I have had thermstat replaced, heater core and complete system flush, no anti-freeze leaks, water pump and pressure checked, fan clutch seems to be good, new belt (not slipping), hoses not collapsing, new radiator cap, not throwing any codes out. A/C off or on no difference. 318 w/AOD, 108,000K, radiator full and overflow tank level when cool. Why in the heck does it overheat so easily, so fast? Can't get 8 miles across town in traffic without over heating! The shop where I take it can't seem to figure it out either. Any ideas?......Anyone?