On hot 100 plus day on freeway with ac going. Mine seems to be fine 202 at top radiator hose and lower 170 so guess radiator is working dropping temps. I have 2005 and gauge stays in correct position but if i run fast on freeway it kind of jumps pushes higher fast towards 3/4 or almost H in Nevada desert on hot day. My hand held temp reader say's normal temps? Could the coolant temperature sensor be issue. I know there is TSB re flash for gauges on 2005 model year to re calibrate gauge cluster. Rather not give those stupid dealers any more money $125 to re set gauges. What is strange never did this when new. Could radiator not be as efficent, water pump not working efficent. Sensor like coolant temp giving bogus resistance readings. Haden Fan HD,Crown thermo installed. Everyone say's crown is junk but so is factory part good 100k maybe and fail open. What temps would I need to worry at top radiator hose? Thermo is deep in bowls motor to hard access.

I have the HDS thermostat with a 203F thermostat and will generally stay there. I have driven down in Salt lake city on a few 100F+ days. That said, when I start to pull hills I will get up to 210 or more and about 5/8's up the temp gauge if I don't kill the AC. Even with the AC off it will still climb a bit over 203.

Sent from my Nexus 6 using Tapatalk

_________________
2006 CRD - GTB2056 turbo by Dieselguy86, Eco Trans Tune, Lift Pump, Week's, HDS Tstat, Racor Filter, ARP's, OME 790's+Top Plate, JBA 2.5", JBA UCA, Moab's+265/75R16, ARB Bull Bar, 4.10's, TrueTracs

I think you should get rid of that crown thermostat.

Here in FL we have had plenty of 95+ days this summer.
My coolant temps typically run between 190 and 205.
Sometimes, when stuck in slow moving traffic, my temps will get up to 215.
Turning off the AC helps bring it back down.
I dont tow and mountain driving is extremely rare.

I'm using a modified factory thermostat housing (gutted) with a inline 195 thermostat.
I have removed the engine driven fan and am only using the electric fan.

_________________
U.S. Army Retired

Crown thermostats like to fail CLOSED which is definitely no good for the engine, and they tend to not open all the way before they fail completely.

Get rid of that thing.

_________________
Proud supporting vendor of LOST Jeeps
TRAVELING CRD TECH. I come to you!
Need help? Just ask! I've taken it apart more than most.
Email jeep [at] maincomputer [dot] com - BOARD MESSAGING IS BROKEN
Over 225 CRDs currently driving with my valves, timing belt, rockers, or ARP Studs.
Bad noises = REALLY bad things.

I monitor routinely using Torque and sit consistently between 190 and 193 using a 190F thermostat in a factory housing modified as per Sargeindustries design. Granted we don't get the temperatures some of you guys are seeing but still have or share of low 90's. Regularly towing ~5000lb of boat and trailer but don't have many decent hills to really test it on around here.