I have been told that the urea fluid additive breaks down in high temperatures which can reduce the effectiveness up to 50%. So whether you can get the normal range on a hot day is problematic, As when the urea tank goes empty due to higher usage for the same effect, one will find the engine goes into limp mode.
That is why I searched for and found a 2012 Dodge since it would be without that urea requirement.
WBCCI Life Member 5123, AIR 70341, 4CU, WD9EMC
TV - 2012 Dodge 2500 4x4 Cummins HO, automatic, Centramatics, Kelderman level ride airbag suspension, bed shell
2014 31' Classic model 30 twin beds, 50 amp service, 900 watt solar system, Centramatics, Dill TPMS, disc brakes, 16" tires & wheels