Temperature gauge fluctuating

[The Blue Scarab]

Hello everyone. This is the first forum I ever joined. First time jeep wrangler owner. Its not my first car but it is my dream car. I'm have a issue with the temperature gauge that started last night. I get in the car to warm it up to head home. I'm there waiting for the needle to hit 210° so I can go. But it seemed to be stuck just above the 100° mark. I think of it as no big deal and continue to wait but another 10 minutes go by and its still there. I say screw it and drive. 5 minutes into my drive I see the needle go to 210° and I brush it off like nothing. But when I hit a red light I'm looking at the needle and see it drop from 210 straight back down to where it was before which was just above 100°. So me being cautious about this I head home the local way instead of the highway and at every red light it would do this. IDK how many of you guys here have had that problem. This is a first for me and from what I've seen here everyone is helpful. So is this something that normally happens or so I take it to the shop to check it out. I could really use a hand guys.

Thanks for reading this and hope you can help me out

 

[Chris]

Sounds like a potentially faulty temperature sensor to me.

 

[The Blue Scarab]

Sounds like a potentially faulty temperature sensor to me.

Do you recommend me taking it to the shop or is it a at home fix?

 

[Chris]

Do you recommend me taking it to the shop or is it a at home fix?

How mechanically inclined are you? The temp sensor is very easy to replace. However, if you have no mechanical skills whatsoever, then I'd take it to a shop.

 

[The Blue Scarab]

How mechanically inclined are you? The temp sensor is very easy to replace. However, if you have no mechanical skills whatsoever, then I'd take it to a shop.

Somewhat skilled. If under the hood I could most likely do it, but if its like under the car I would be unable too

 

[Chris]

Somewhat skilled. If under the hood I could most likely do it, but if its like under the car I would be unable too

If I remember correctly, it's accessed on the top side. You can find out for sure in the FSM, which you can download here for free:

Jeep Wrangler TJ Factory Service Manuals (FSM) & Technical Documentation

 

[techjess323]

Yes its on the top side but coolant leaking out can be kind of intimidating if you dont know what youre doing. I used deep socket 19mm an it came out smooth. Tried to swap fast since the coolant was running out. Also, make sure engine is cold. I kow its a no brainer for most on here, but to the newbs like me it was crucial that i read that. Would have started working on a hot engine had i not. Whew!

 

[Jerry Bransford]

My bet is your thermostat is the cause of the problem, not the temperature sender. I'd replace the thermostat with a fresh Stant or other good quality 195 degree thermostat. Make sure to avoid ANY thermostat claiming it is "failsafe". Failsafe thermostats won't fail in the closed position which is good but they fail way too often and easily in the open position which is bad.

 

[KimsJeep]

Just a heads up, this thread was from June of this year. I"m thinking the problem was fixed by now.

 

[tworley]

Im curious as to why someone waits to reach full operating temp before driving...