Odd Temp Reading..?
Thread Starter
Senior Member


Joined: Apr 2009
Posts: 819
Likes: 7
From: VA
Year: 1998
Model: Cherokee (XJ)
Engine: 4.0
So ive been noticing that my temperature gauge is reading a rather odd number under any kind of driving which I calculate to be round 150. Sometimes it will run at a normal temp of 190 to 210 & then out of the blue it will just drop down to that 150 mark & do it within a few seconds!! Other times it doesn't even get to normal running temp & just stops at the 150 mark. No matter what tho, there is no other readings other then normal running temp or the 150 mark seen here in this pic:

Only 2 things I can think of here is replacing the thermostat & if its still doing the same then get a new temp sensor. Its just so odd that it drops down to that same spot all the time so anyone with some input would be appreciated!!
Thanks!

Only 2 things I can think of here is replacing the thermostat & if its still doing the same then get a new temp sensor. Its just so odd that it drops down to that same spot all the time so anyone with some input would be appreciated!!
Thanks!
CF Veteran
Joined: Mar 2010
Posts: 47,923
Likes: 38
From: Broward County Fl.
Year: 1989 xj sport 2dr
Model: Cherokee
Engine: 12 hole bosch Injectors
Thread Starter
Senior Member


Joined: Apr 2009
Posts: 819
Likes: 7
From: VA
Year: 1998
Model: Cherokee (XJ)
Engine: 4.0
Someone said to me:
The gauge is not linear & the first mark is about 195° so when it does that it is because the thermostat opens up completely.
So I said back:
I though about it being that exactly, that the drop is when the t-stat opens up, BUT that's a huge drop & this being my 2nd XJ, ive never seen a running temp where that guage is in the pic!!
The gauge is not linear & the first mark is about 195° so when it does that it is because the thermostat opens up completely.
So I said back:
I though about it being that exactly, that the drop is when the t-stat opens up, BUT that's a huge drop & this being my 2nd XJ, ive never seen a running temp where that guage is in the pic!!
Thread Starter
Senior Member


Joined: Apr 2009
Posts: 819
Likes: 7
From: VA
Year: 1998
Model: Cherokee (XJ)
Engine: 4.0
Someone said to me:
The gauge is not linear & the first mark is about 195° so when it does that it is because the thermostat opens up completely.
So I said back:
I though about it being that exactly, that the drop is when the t-stat opens up, BUT that's a huge drop & this being my 2nd XJ, ive never seen a running temp where that guage is in the pic!!
The gauge is not linear & the first mark is about 195° so when it does that it is because the thermostat opens up completely.
So I said back:
I though about it being that exactly, that the drop is when the t-stat opens up, BUT that's a huge drop & this being my 2nd XJ, ive never seen a running temp where that guage is in the pic!!
CF Veteran
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
Ask yourself a ?......when the gauge ispointing at 150, how well is your heater working? If it's working good, most likely something is wacked about the gauge reading. If heater performance is poor, could be the t-stat stuck open or missing. My guess is something wacked with the gauge, sensor, or electrical connection.
Ain't no way that point (1/4 mark) on the gauge represents 195......not even Chrysler/Jeep engineers are that goofy. LOL
Ain't no way that point (1/4 mark) on the gauge represents 195......not even Chrysler/Jeep engineers are that goofy. LOL
Last edited by djb383; Jun 21, 2013 at 02:35 PM.
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CF Veteran
Joined: Apr 2009
Posts: 4,734
Likes: 12
Year: 2015, 2012
Model: Grand Cherokee (WK2)
Engine: 3.6L
You need to be more concerned about that airbag light being on.
Get an IR temp reader and point it at the thermostat housing when showing that temp on the gauge to see what it's really doing.
If the radiator is not icing up or boiling over, it's probably OK.
Get an IR temp reader and point it at the thermostat housing when showing that temp on the gauge to see what it's really doing.
If the radiator is not icing up or boiling over, it's probably OK.
Thread Starter
Senior Member


Joined: Apr 2009
Posts: 819
Likes: 7
From: VA
Year: 1998
Model: Cherokee (XJ)
Engine: 4.0
Just noticed that when I was parked with the motor idling, the gauge at that mark, & the AC on, (yes my AC works!!), that the electric fan was running, so the motor has to be at running temp if not more for the aux fan to click on,,, right??
Do u think its worth changing the stat anyways to see if theres a difference??
(Airbag fuses are pulled cause I had my 7yr old Son in the front seat)
Do u think its worth changing the stat anyways to see if theres a difference??
(Airbag fuses are pulled cause I had my 7yr old Son in the front seat)
Seasoned Member
Joined: May 2012
Posts: 436
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From: Ware Shoals, SC
Year: 1993
Model: Cherokee
Engine: 4.0L
Just noticed that when I was parked with the motor idling, the gauge at that mark, & the AC on, (yes my AC works!!), that the electric fan was running, so the motor has to be at running temp if not more for the aux fan to click on,,, right??
Do u think its worth changing the stat anyways to see if theres a difference??
(Airbag fuses are pulled cause I had my 7yr old Son in the front seat)
Do u think its worth changing the stat anyways to see if theres a difference??
(Airbag fuses are pulled cause I had my 7yr old Son in the front seat)
Thread Starter
Senior Member


Joined: Apr 2009
Posts: 819
Likes: 7
From: VA
Year: 1998
Model: Cherokee (XJ)
Engine: 4.0
Thread Starter
Senior Member


Joined: Apr 2009
Posts: 819
Likes: 7
From: VA
Year: 1998
Model: Cherokee (XJ)
Engine: 4.0
CF Veteran
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
U may not need a new stat. If the heater is blowing hot, when at the 1/4 mark, your gauge is lying to u. Heater performance will suck at 150 actual coolant temp.


