Mine reads 178F a lot... Last time I had it in for a coolant system pressure check the mechanic said "You know your readout reads low" He had his unit hooked up, which reads off of the same sensor and my readout was 3 degrees lower than his calibrated scanner... Go figure.


Just saying this because mine reads the 178F but is not throwing codes, so there could be a glitch in the readout that isn't a "real problem" that would cause trouble.

 

I just dropped it off at the mechanics.
The temperature fluctuated between 175 and 203, mostly in the 180's, under the following conditions:

air temperature 98 degrees
11 freeway miles
speed at 60 mph
little to no traffic.
no A/C

Is the swing in temperature normal? just curious.

 

Below 180F is NOT normal. Swinging between 180-190 is normal under those conditions.

The t-stats job is to keep the temp ABOVE 180F. The radiator and fan keep it below 219F. Airflow alone should keep it around 190F.