I have a 99 6cyl and it's been running on the 220deg range. I put 33 on it during the winter I had 31 and had no problems. When summer came around the problem started. I had already changed the radiator out and heater core. So I next changed out the thermostat,then water pump, then the fan clutch. But I still had the problem. My water level stays good and my oil looks good. The jeep had smaller gears in so I changed them to 4-11 thinking that might havebeen causing it to over heat but I still have the same problem. Also if the temp outside is below 80deg it stays at 195deg but any hotter outside it runs hot. Can anyone help I don't know what to try next?