Just one more data point before throwing $$ at it. Check you main fan. This fan is knownto fail at this kind of mileage. To see it spinning is not enough. It gets weak with age. Wear a heavy and try to stop it. If is stops easily, it is bad and it is your over heating issue. Also, check your secondary fan. If it doesn't kicks in when the a/c is on, you will over heat b/o the extra heat from the condenser and extra load. Don't ask how I know!