RonBrooksGA

Thank you so much! I read #1 and I feel a lot better! I will re-check for any debris on radiator and condenser but I believe I cleared everything and even washed the fins.

DGXR

I am still wondering why the temps would be higher on the highway (lots of airflow) and they would be lower in traffic or even idling for 30 minutes. If the issue were caused by debris blocking airflow to the radiator, the issue would appear in all circumstances. So then I thought of the air dam (front spoiler) which pulls more air into the radiator/condenser. If you have a damaged or missing air dam, that will affect your cooling temperatures on the highway for sure. Also remember that the fans will automatically turn on at 228F but they will not kick on at speeds above 35mph.

ddahlgren

If air bound the fast fix with any new thermostat is to drill 2 1/8 inch holes in the flange so air and a tiny bit of water can bypass the closed thermostat when filling. Fill slowly and squeeze the lower hose every now and then and it will get some air moving. The filling slow is to let the air work it's way out of the bleed holes and heater core. When full run with cap off until thermostat is open if a 180 if not just to see if it will take a little more coolant a fast idle helps that. If working alone use a matchbook cover or similar to get the idle to 2000 and it will take more coolant. Put the capon and do a drive and cool down to top off. Always worked for me..