Coolant Temp

[agamble]

Hopefully someone can shed some light on my problem. Them temperature gauge in my 89' will never rise above ~180 degrees when at operating temperature. Now perhaps I am creating a problem where there isn't one, but all the jeeps I've ever owned have operated at ~210 degrees, including this one at first. One day it just stopped climbing past the 180 mark. Every once in awhile if it gets warm after driving for 20 plus minutes, if I shut it off then start it up, the temp gauge goes to 210 for a bit then drops to 180. I have replaced the thermostat with the recommended 195 degree, the gauge sending unit, the coolant temp sensor (on the block by motor mount), and checked grounds. Am I missing something?

[87Warrior]

Are you positive your new thermostat is operating as it should? My bet is the autoparts store thermostat is opening a bit early.

[Marine1Texas]

Check your gauge that it is working correct. My gauge that came with truck is off by 10 degrees, even after all fix's with grounds and what not. I use a after market gauge that works way better.

[agamble]

Are you positive your new thermostat is operating as it should? My bet is the autoparts store thermostat is opening a bit early.

I have swapped it out twice. I thought that the first time but even with a second brand new thermostat it stays the same.

 

Check your gauge that it is working correct. My gauge that came with truck is off by 10 degrees, even after all fix's with grounds and what not. I use a after market gauge that works way better.

Honestly that has not occurred to me, I might try a different gauge and see if that helps.

[HOrnbrod]

One day it just stopped climbing past the 180 mark.

 

Does that mean your temp gauge was indicating correctly (~210* op temp) before that day? Also, do you know the p/n of the gauge temp sensor you used?

[agamble]

 

One day it just stopped climbing past the 180 mark.

 

Does that mean your temp gauge was indicating correctly (~210* op temp) before that day? Also, do you know the p/n of the gauge temp sensor you used?

Yes, it was indicating correctly then just stopped. I don't recall the temp gauge sensor p/n.

[Eagle]

Am I missing something?

Instrument cluster ground.

[HOrnbrod]

 

Am I missing something?

Instrument cluster ground.

 

 

Doubtful. A bad dash ground would cause other faults. But worth a shot to refresh.

[jimoshel]

B4 I would do anything, I would stick a thermometer in the radiator and verify the temperature. Either block off the radiator or remove the thermostat first.

[Jeep Driver]

Probably the sender, I've gone through a couple of them.

 

Mine reads cool also but my Efan comes on at 180, it's a 195 Spal and I trust it over the sender/gauge.

[JEEPTRK]

Well mine sits around the same, but i was just going to replace the coolant temp sensor.... worth the hassel?

[JEEPTRK]

Mine is an 89 as well. Ive seen 90-92 run at 210.

[MJCARENA]

I think you changed the wrong temp sender. The one for the gauge is at the back of the head.

[HOrnbrod]

I have replaced the thermostat with the recommended 195 degree, the gauge sending unit, the coolant temp sensor (on the block by motor mount)

 

I though the same thing at first...........

[cruiser54]

I think you changed the wrong temp sender. The one for the gauge is at the back of the head.

Sender is at the back of the head.

 

Sensor is down on the driver's side of the block. 

[ScottJeep]

Scared the crap out of myself due to a POS sender from AutoZone. 

 

Grabbed one from the parts bin I had from a JY parts grab.

 

Works fine. 

 

Make sure it's CLEAN no sealant of any type!