Ok, so anytime I spend 30 minutes or more in stop and go traffic, my radiator boils out. Got a new cap, didn't help, replaced the a/c fan, didn't help, replaced the thermostat, didn't help, replaced the fan clutch, didn't help, I think my belt might be a little loose, so I'm gonna tighten that next, my temp sensor never reads above normal. I don't understand what's going on. One thing I did notice is that there is no distinctive cold to hot change when touching the upper radiator hose when the thermostat should go from closed to open, but I only tested it immediately after installing it and haven't had time to do it again. Thermostat is easy and cheap, no biggie. But does anyone have any other ideas what could be happening?

95 Sportage w/welded and 5.89 geared dana 44's on 38.5" TSL's.- SADLY SOLD
CURRENTLY - 2000 sportage, 5.38 gears, welded diffs, 35" tires, 5.5" lift