Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here XJ (84-01)
All OEM related XJ specific tech. Examples, no start, general maintenance or anything that's stock.

Odd Temp Reading..?

Thread Tools
 
Search this Thread
 
Old Jun 21, 2013 | 05:32 AM
  #1  
SeniorXJ's Avatar
Thread Starter
Senior Member
15 Year Member
Liked
 
Joined: Apr 2009
Posts: 819
Likes: 7
From: VA
Year: 1998
Model: Cherokee (XJ)
Engine: 4.0
Question Odd Temp Reading..?

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!
Reply
Old Jun 21, 2013 | 07:28 AM
  #2  
cruiser54's Avatar
::CF Moderator::
 
Joined: Aug 2011
Posts: 43,971
Likes: 1,579
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Default

Go buy a stat from the dealer. They're the best uality and keep your Jeep at the right temp. Also they insure fast warmups in the winter.
Reply
Old Jun 21, 2013 | 07:31 AM
  #3  
Muaddib420's Avatar
Seasoned Member
 
Joined: Jun 2012
Posts: 485
Likes: 3
Model: Cherokee
Default

My bet is temp sensor with that quick of a drop.
Reply
Old Jun 21, 2013 | 08:26 AM
  #4  
freegdr's Avatar
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
Default

Originally Posted by cruiser54
Go buy a stat from the dealer. They're the best uality and keep your Jeep at the right temp. Also they insure fast warmups in the winter.
x2
Reply
Old Jun 21, 2013 | 10:46 AM
  #5  
SeniorXJ's Avatar
Thread Starter
Senior Member
15 Year Member
Liked
 
Joined: Apr 2009
Posts: 819
Likes: 7
From: VA
Year: 1998
Model: Cherokee (XJ)
Engine: 4.0
Default

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!!
Reply
Old Jun 21, 2013 | 02:07 PM
  #6  
SeniorXJ's Avatar
Thread Starter
Senior Member
15 Year Member
Liked
 
Joined: Apr 2009
Posts: 819
Likes: 7
From: VA
Year: 1998
Model: Cherokee (XJ)
Engine: 4.0
Question

Originally Posted by SeniorXJ
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!!
Anyone else think this may be a normal reading & that the gauge in the pic is actually pointing to 195 deg??
Reply
Old Jun 21, 2013 | 02:30 PM
  #7  
djb383's Avatar
CF Veteran
 
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
Default

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

Last edited by djb383; Jun 21, 2013 at 02:35 PM.
Reply
Old Jun 21, 2013 | 02:38 PM
  #8  
Firestorm500's Avatar
CF Veteran
 
Joined: Apr 2009
Posts: 4,734
Likes: 12
Year: 2015, 2012
Model: Grand Cherokee (WK2)
Engine: 3.6L
Default

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.
Reply
Old Jun 21, 2013 | 04:28 PM
  #9  
SeniorXJ's Avatar
Thread Starter
Senior Member
15 Year Member
Liked
 
Joined: Apr 2009
Posts: 819
Likes: 7
From: VA
Year: 1998
Model: Cherokee (XJ)
Engine: 4.0
Default

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)
Reply
Old Jun 21, 2013 | 05:08 PM
  #10  
bulrid8's Avatar
Seasoned Member
 
Joined: May 2012
Posts: 436
Likes: 0
From: Ware Shoals, SC
Year: 1993
Model: Cherokee
Engine: 4.0L
Default

Originally Posted by SeniorXJ
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)
Fan runs anytime the ac is on.
Reply
Old Jun 21, 2013 | 05:54 PM
  #11  
Firestorm500's Avatar
CF Veteran
 
Joined: Apr 2009
Posts: 4,734
Likes: 12
Year: 2015, 2012
Model: Grand Cherokee (WK2)
Engine: 3.6L
Default

Put the airbag fuse back in. Put the son in the back seat.

Everyone will be much safer.
Reply
Old Jun 21, 2013 | 06:08 PM
  #12  
SeniorXJ's Avatar
Thread Starter
Senior Member
15 Year Member
Liked
 
Joined: Apr 2009
Posts: 819
Likes: 7
From: VA
Year: 1998
Model: Cherokee (XJ)
Engine: 4.0
Default

Originally Posted by Firestorm500
Put the airbag fuse back in. Put the son in the back seat.

Everyone will be much safer.
Jeep was loaded up with Jiu-Jitsu mats in the back.

Airbags wont deploy anyway with the winch bumper.

Thanks for the safety tip, now can we keep it on topic please.
Reply
Old Jun 21, 2013 | 08:08 PM
  #13  
djb383's Avatar
CF Veteran
 
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
Default

Does the heater blow hot when the needle is at the 1/4 mark and the motor is at operating temp (running for a while)?
Reply
Old Jun 21, 2013 | 08:47 PM
  #14  
SeniorXJ's Avatar
Thread Starter
Senior Member
15 Year Member
Liked
 
Joined: Apr 2009
Posts: 819
Likes: 7
From: VA
Year: 1998
Model: Cherokee (XJ)
Engine: 4.0
Default

Originally Posted by djb383
Does the heater blow hot when the needle is at the 1/4 mark and the motor is at operating temp (running for a while)?
Don't know, didn't try, but will do so tomorrow when I grab a new t-stat.
Reply
Old Jun 21, 2013 | 09:38 PM
  #15  
djb383's Avatar
CF Veteran
 
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
Default

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.
Reply



All times are GMT -5. The time now is 07:32 AM.