I'm chasing down high water temps and made an interesting observation the other day. When starting the engine cold (say 80F ambient), the water temps would rise to about 135F in a matter of seconds of driving. When coasting on the freeway, I see 200F pretty often.

Is this what you guys observe?

Note, I'm using a scangauge to pull the raw temp numbers.

 

Temps rise pretty quickly and that seems normal. Cruising on the highway I see ~185F. If your thermostat is 185 then that means your radiator can't keep up, you have air in the system, or you lack airflow to the radiator.