I have a 2009 Dodge Challenger R/T (5.7 Hemi/Automatic/32k miles).

Today I observed the temperature gauge register to almost the H. I checked the coolant level and it was normal. I checked the oil and it appeared normal in color and it was at the correct level. The upper and lower radiator hose did not display and damage.

I did not observed any leaks. I then drove the Dodge on the highway and it registered back down below the half way mark. When I parked the Dodge it idled for a few minutes and it remained below the half way mark.

However, a few days prior, I could detect the odor of anti freeze through the interior dash vents.

Any opinions on where to start?

Thanks!

Did you actually use anything to measure the temp? Not sure if the factory gauge is anything useful, too many these days are not.

If you smelled coolant from the vents sounds like a heater core is leaking to me. Not a fun job.

Don't get that engine hot.Find out what's causing this.They warp heads pretty easy.DAMHIK

Failing thermostats will frequently give warnings like you saw.

first thing I thought as well, had 3 modern mopars all do same thing. In the challenger it should only be a 15 min job

find/fix the leak (required) then as said checking the stat would be an easy first step for the overheating. I would shoot it with a temp gun (reportedly the HF one works adequately) or try another (mech) gauge

Also suggest you check your fan function. Hot at a stop and cool on a roll suggests the fan is not fully functional. If you run it at idle with AC on, the fan should kick on around 210F. If it does not, need to trace the problem.