UPDATE....well today was a cool day outside (different from the recent 100 degree plus days we've had out here for a while) and although my car's engine temp still moved up to 80 c, the idle at a stop, while in gear, idled like it does before it warms up in the morning...smooth. This after plenty of freeway driving (45 miles plus). Does this ring a bell or help to narrow down any of the usual suspects?