Coolant Temp Gauge

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Joined
Jun 23, 2020
Messages
340
Reaction score
187
Location
Avon Lake, Ohio
Hey yall, just got a quick question. This past weekend I did some work to the cooling system of my Jeep. From what I could tell the system filled, and bled just fine.
Gauge would heat up, then stay a hair below half way, the way its always has.

BUT, is the coolant temp gauge a real gauge, or is it more of a dummy gauge? Like would it tell me if the jeep is overheating? I have no other way to tell if it would be overheating, as my scan tool doesn't read engine temps on this Jeep.

I've been suspicious of the lack of movement I've been able to catch from the radiator fan, even at operating temp per the gauge.

Overall just freaking myself out as i cant afford to brick this car at this point in time.
 

GitEmSteveDave

Full Access Member
Joined
Feb 23, 2018
Messages
391
Reaction score
112
Location
Howell
Dummy gauge.

I have a OBDII Bluetooth dongle & a cheap tablet that has GPS to run Torque in mine. Gives me a readout for coolant temp.

I made a gallery of the gauge position and actual temp it's running with my 03:
xc_hide_links_from_guests_guests_error_hide_media
 

kejobe

Full Access Member
Joined
Sep 5, 2016
Messages
415
Reaction score
62
Location
NE Ohio
The gauge is NOT 100% accurate. It will move accordingly when operating properly though and is easily usable as a guide. If it goes above the 1/2 mark and keeps climbing, you are more than likely starting to overheat.

I have electric fans on mine and they don’t run as often as I would have expected them to when I bought it, but all is good.

With all this said, my opinion is your freaking yourself out as you said.
 
Joined
Jun 23, 2020
Messages
340
Reaction score
187
Location
Avon Lake, Ohio
Dummy gauge.

I have a OBDII Bluetooth dongle & a cheap tablet that has GPS to run Torque in mine. Gives me a readout for coolant temp.

I made a gallery of the gauge position and actual temp it's running with my 03:
xc_hide_links_from_guests_guests_error_hide_media
The pictures are helpful to visualize around what temp it may be at
 
Joined
Jun 23, 2020
Messages
340
Reaction score
187
Location
Avon Lake, Ohio
The gauge is NOT 100% accurate. It will move accordingly when operating properly though and is easily usable as a guide. If it goes above the 1/2 mark and keeps climbing, you are more than likely starting to overheat.

I have electric fans on mine and they don’t run as often as I would have expected them to when I bought it, but all is good.

With all this said, my opinion is your freaking yourself out as you said.
Thank you for the reply! I got a more recent update for my scan tool so I can finally read the Jeeps engine temp now.

Ill take it for a test drive tomorrow and monitor it more closely.
 

tommudd

Moderator
Staff member
Moderator
Joined
Jul 14, 2005
Messages
22,456
Reaction score
3,642
Location
Southeastern Ohio
All of my KJs run ( when fully warmed up ) at about 198 degrees give or take one or two degrees
and yes the temp gauge is an idiot gauge
 

Michael Noland

New Member
Joined
Feb 5, 2020
Messages
22
Reaction score
9
I've read that the CRD's show hotter than actual and need to be reprogramed. My Jeep dealer didn't know what I was talking about. Only time mine goes above center is when I'm towing something in the summer time.
 
Joined
Jun 23, 2020
Messages
340
Reaction score
187
Location
Avon Lake, Ohio
All of my KJs run ( when fully warmed up ) at about 198 degrees give or take one or two degrees
and yes the temp gauge is an idiot gauge
After hooking up the scan tool and watching the live data, at operating speeds the temp wouldn't get above 203-205. At idle it would get to 217 then drop back down to 205 when the fan kicked on.

So overall I think the radiator replacement was a success, and there is no air in the system.

Thank you to all who replied to this thread and helped me out!
 

Jeremy-WI

Full Access Member
Joined
May 20, 2017
Messages
368
Reaction score
184
Location
Home
What do you mean by idiot gauge? Just that it doesn't set off alarms if it does go way over normal temp?
 

tommudd

Moderator
Staff member
Moderator
Joined
Jul 14, 2005
Messages
22,456
Reaction score
3,642
Location
Southeastern Ohio
What do you mean by idiot gauge? Just that it doesn't set off alarms if it does go way over normal temp?
Idiot gauge since it does not tell accurate temps, sitting exactly in the middle it can have a 50-60 degree difference above and not move off center
 

Yetiboy01

New Member
Joined
Jun 28, 2021
Messages
20
Reaction score
9
Idiot gauge since it does not tell accurate temps, sitting exactly in the middle it can have a 50-60 degree difference above and not move off center
Sounds like your gauge is stuffed, mine works fine tested against torque Pro app
 

tommudd

Moderator
Staff member
Moderator
Joined
Jul 14, 2005
Messages
22,456
Reaction score
3,642
Location
Southeastern Ohio
Sounds like your gauge is stuffed, mine works fine tested against torque Pro app
????? garage is stuffed has to do with temps how ?
And these that were tested over the last 17 years I have been playing with the KJs were other peoples, such as friends, customers etc,
that were having issues and I was checking them out to repair
I know what all of my KJs reads from the scan gauges right on top of their dashes ; )
 

GitEmSteveDave

Full Access Member
Joined
Feb 23, 2018
Messages
391
Reaction score
112
Location
Howell
What do you mean by idiot gauge? Just that it doesn't set off alarms if it does go way over normal temp?
On my Dodge 3500 Dualie, the temp is an actual gauge with actual temperature markings on it, 140f, 190f & 230f(in the red). I could tell when the thermostat first opened because the needle would swing down as the coolant from the tank rushed in, especially in winter.

I too use Torque Pro, and I posted a gallery above showing actual coolant temp vs. what the gauge shows using that app. From ~170f to 220f(the highest mine gets before the fan kicks in) the needle is touching the center black line and doesn't move.
 

Jeremy-WI

Full Access Member
Joined
May 20, 2017
Messages
368
Reaction score
184
Location
Home
On my Dodge 3500 Dualie, the temp is an actual gauge with actual temperature markings on it, 140f, 190f & 230f(in the red). I could tell when the thermostat first opened because the needle would swing down as the coolant from the tank rushed in, especially in winter.

I too use Torque Pro, and I posted a gallery above showing actual coolant temp vs. what the gauge shows using that app. From ~170f to 220f(the highest mine gets before the fan kicks in) the needle is touching the center black line and doesn't move.
That likely means they save money on the gauges by not calibrating them to the resistance curve of the sensor itself as the thermistor doesn't work on a linear scale
 

Latest posts

Members online

Top