When is the coolant too hot?

I love my ScangaugeII but I'm curious about what a safe operating temperature is. It usually runs around 191F and up until the other day I had seen 213 a couple of times. Last weekend while crawling up a pass in bumper to bumper traffic it was up to 222 and I was getting pretty nervous. I had the AC turned off and a very light load.

Thanks

brucedog,
How fast was the traffic moving (bumper to bumper) or was it stop and go traffic?
What gear were you running in (I hope you don't say "Drive).
The AC adds very little heat load so it's pretty unnecessary to turn it off when the engine coolant temp
creeps up.
Always remember that by manually downshifting and keeping the RPM > 2400 as much as possible you are reducing
the overall heat load on the radiator in 2 ways.
#1 Manually downshifting the transmission reduces the overall load through the transmission which allows it to run
cooler which reduces the heat load in the engine coolant radiator due to the trans fluid heating/cooling coil/heat exchanger
in the lower radiator tank.
If you are in stop and go traffic, it's also a good idea to shift out of drive when stopped.
Use your Scan Gauge II %LOD to see that the transmission in gear idling results in > 30% LOD.
Shifting the trans to neutral brings the %LOD back down to < 25%.
Best case is ~ 18-20% LOD out of gear.
No sense "churning" the trans fluid when you aren't moving.
#2 More RPM allows the engine driven viscous clutch fan to draw more air through the cooling stack and
this cools both the engine coolant and the transmission fluid.
The goal here is to reduce the overall heat load while at the same time keeping enough air flowing through the cooling stack
to carry the extra heat load away.
Your OM-642 3.0 V6 is not considered to be "overheating" until the temp reaches 250 deg. F.
On Pg. 187 of your 2015 Operator's Manual:
"The temperature displayed may climb to
250 ‡ (120 †) when the vehicle is being
driven in normal conditions and if the coolant
contains the correct concentration of corrosion
inhibitor and antifreeze. At high outside
temperatures and when driving in mountainous
terrain, the coolant temperature may rise
to the end of the scale."
Hope this helps,
Roger

At 220 or so you should have heard the belt-driven fan cut in, and in all except the most unusual circumstances it will bring your engine temps back down to 190 in short order. Especially if you are running the engine in a gear where the rpm's are around 2500-3500 you would really notice the extra fan noise when it cuts in.

It provides a whole additional level of engine cooling that is only rarely used except on hot days and slow drives up hills. You might have been just short of the temperature at which it engages.

If you did not hear that, you might have your fan-clutch checked at next service, or wait for a hotter day to test it on that same hill. If you hit 230 or more and you still don't hear it then something is wrong.

Thanks so much to both of you for the feedback and I suppose I should have just looked at the manual. I was going 1-3 mph for about an hour so didn't think to shift into neutral or out of D. Good advice about RPM's...I usually just look at LOD and downshift when it hits 80% or so.

Rob, I never heard the fan engage and will try to listen for it next time. I only have 8500 miles so not been serviced yet Id did cool down very quickly once we got moving.

Thanks again!