Random coolant temp spike

[namrebo]

Yesterday I was sitting at a red light (which was godly long, maybe around5 mins) AC on was in drive. Got the beep, and looked down at cluster at it was at 249. As soon as I moved it went down, and I can see the gauge the actual analog one kinda jumping around. Tested it again then on a backroad stopping waiting 5 mins both AC on and off…nothing…
Driving it later in the gauge did seem to kinda bounce around again but never got that hot
any ideas?
Most recent thing I did was remove grill to install a new winch and remove old. Same winch so not like the profile is blocking the airflow.

Thanks

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[namrebo]

For reference fan was running in “jet engine mode” and temp was not dropping. Was it actually overheating or could sensor be messed up?

 

[eugeeezy]

Have you checked the coolant expansion tank to see if there’s any coolant in there?

 

[namrebo]

I didn’t check much as I don’t drive the vehicle every day. When I get home today from work, I’m going to do some digging.. after reading a bit online it seems like the plastic seem on that expansion tank is prone to failure

 

[namrebo]

Cold engine, off since last night. Resivoir has no coolant in it. Can see it in the pipe at the bottom but none in actual tank

 

[ScotM]

When was the last time you checked it? Definitely fill and monitor daily. Look for leaks at water pump, and at the T near the engine cover - assuming it is a 2.0. - of course check the black reservoir for leaks

 

[namrebo]

To be honest. Never. I never had problems with any of my new vehicles. At least for a long long while. I’m going to fill it up and see if I can ID a leak. Nothing obvious right now that I can see.
Yes 2.0 sorry if I didn’t mention that.
Any recommendations for coolant?, There’s obviously some in the system already and it will be mixed.

 

[Nokones]

Maybe you have an air pocket. Was your cooling system serviced recently? Some cooling systems require to be burped/bled after it was serviced and filled with coolant.

 

[ScotM]

To be honest. Never. I never had problems with any of my new vehicles. At least for a long long while. I’m going to fill it up and see if I can ID a leak. Nothing obvious right now that I can see.
Yes 2.0 sorry if I didn’t mention that.
Any recommendations for coolant?, There’s obviously some in the system already and it will be mixed.

Use the premixed 90032 from mopar

Mopar 68163849AB 10 Year/150,000 Mile Coolant 50/50 Premixed - Embittered, 1 Gallon | Genuine 10 Year / 150,000 Mile Blend, OAT 50/50 Premixed, -34F to 265F, OEM Radiator Fluid for Jeep, Chrysler, Dodge, Ram https://a.co/d/08Ni1eIR

 

[namrebo]

No not serviced since water pump bolt recall thing in like 2022

 

[eugeeezy]

You’re going to want to check all the usual fail points.

- heater hose T fitting.
- expansion tank and the plastic fitting under it.
- water pump inlet tubes into the water pump.
- the actual water pump itself if it’s failed and weeping.

check for signs of dried coolant in those areas. Also check the backside seam of the expansion tank that’s facing the firewall.

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