Temp Spike On Highway Hill

[Dahammer]

Try 1st to replace the engine coolant temp sensor located in the engine. That would be my 1st choice in replacing if it was me.

 

[sixsix]

Try 1st to replace the engine coolant temp sensor located in the engine. That would be my 1st choice in replacing if it was me.

Not when there is documented proof of the thermostats going bad and it being replaced by an updated part.

 

[Dahammer]

Not when there is documented proof of the thermostats going bad and it being replaced by an updated part.

I'll agree with you on that. However, either the therm failed at 65,000 miles, the engine coolant temp sensor located in the engine failed, or both simultaneously. Therms nor sensors last forever. And If the therm died, it should have stayed open.
Therms open and close constantly based on temp of the engine.
And that goes back to the 1968 Ford Torino when ALL therms failed from ALL manufacturers of therms, and when they failed they stayed closed, and engine coolant boiled out of radiators.

 

[sixsix]

I'll agree with you on that. However, either the therm failed at 65,000 miles, the engine coolant temp sensor located in the engine failed, or both simultaneously. Therms nor sensors last forever. And If the therm died, it should have stayed open.
Therms open and close constantly based on temp of the engine.
And that goes back to the 1968 Ford Torino when ALL therms failed from ALL manufacturers of therms, and when they failed they stayed closed, and engine coolant boiled out of radiators.

These are not the same type of thermostats that they had in 1968. Mine failed at 69k miles.

He also said his trans temp was also elevated, which is another sign of the failed thermostat. And pretty sure the thermostat opens when it gets hot, it doesn’t start out open when cold. It’s gets in a bind on its way open, not allowing it to fully open. Hence the redesign.

 

[Dahammer]

I got a 2022 Jeep GWS3 and drove to Philly last year in the summertime early evening. While on the NJ Turnpike, I open her up roughly 85mph, sometimes 90, throughout the trip. I used dash gauges to see the temps since the coolant spike to 240 degrees and stay constant, and the oil temp was hotter than the coolant. Eventually, the fans kick in, and you can hear the fans screaming, and then they drop temp coolant to 198 and the oil temp to about 215. If I got off the gas pedal, say to around 65-70 mph, everything started to cool down, and the fans didn't kick in.

Shortly after the trip, I brought her into the dealership for LOF and did mention what I saw and had some pics on my cell and showed him. They could not duplicate those temps.

This year all my cameras died. Brought her in for service under manufacturing warranty. She had 11,720 miles on her. 6 weeks of the fiasco with Jeep, numerous electrical ground faults, PCM mod failure, bad updates, and to top it off, Chrysler had all the wrong part numbers for this vehicle and had to repopulate the entire catalog with correct numbers.

Finally, Got her home and noticed that all gauges now reporting correct numbers, including the alternator charging rate.

Now that vehicle is in Lemon Law, and I got a New Expedition with fewer bells and fewer whistles, and am happy as a pig in mud.

Could this be a correlation? Jeep vs Ford? Not sure, But...

 

[zak99b5]

New 180* t stat should be coming today. Next Wednesday I tow my smaller pop up camper up north for a trip. I’ll monitor the trans temp since I don’t have the numerical display of coolant temp above the bar.

 

[zak99b5]

Did not get a chance to install the new t stat before the camping trip with the rain. Driving up to the campground, me and three middle schoolers in the car with gear and towing a 10’ box pop up trailer, I was watching the temps. It’s a 70 mile trip, so 1 1/2 hours.

Kept speed around 70-75. On hills after about an hour, got the 23x* degree warning a few times. Would cool back down quickly when I eased up on the throttle.

I also had the trans temp displayed for most of the trip, at it was running around 210-212* with a couple increases to 214* on longer hills.

On the way home, with fewer long uphill sections, I never got the temp warning. Tranny was at 208-210* with it hitting 212* briefly.

Im assuming the cts is in the head or just off it. Could be that the t stat is sticking or slow to open, so temps at the head rise while flow to/from the rad is impeded. The tranny temps were only 2* different on the two trips, using the same coolant as the engine. If ALL the coolant were 235*, I would expect the tranny temp would rise, being heated (rather than cooled) in the worst case, or at least tranny temps would not drop a couple degrees after climbing a hill as quickly as they did.

 

[zak99b5]

Got the new t stat in today. Could not for the life of my find the petcock on the rad, so I just let all the coolant come out when I pulled the t stat.

Made sure to install the new with the jiggle valve at the top, which is how the original was. Original is actually a 195*, part no. HL3E-8575-AA. The copper plunger part does not move freely, and it can even get bound up on return and sit cocked.

Used the entire gallon of premix coolant I bought at the dealer. Drove it around to get it up to temp. Lower hose got warm. No leaks. I’ll recheck the level when it cools down.

 

[Dahammer]

Got the new t stat in today. Could not for the life of my find the petcock on the rad, so I just let all the coolant come out when I pulled the t stat.

Made sure to install the new with the jiggle valve at the top, which is how the original was. Original is actually a 195*, part no. HL3E-8575-AA. The copper plunger part does not move freely, and it can even get bound up on return and sit cocked.

Used the entire gallon of premix coolant I bought at the dealer. Drove it around to get it up to temp. Lower hose got warm. No leaks. I’ll recheck the level when it cools down.

When you go out and drive, turn on the heater and set temp on high. Open the windows also. By doing this, your getting rid of any air trap in the heater core and lines.

 

[platinumexpy]

These vehicles are notorious for transportation overheating when you make sudden brakes and speed ups. Specially when you are in highway traffic and you try to pass vehicles in front of you. I noticed it once before but the best way to remedy this is to be cool with the sudden breaking and gas on highway traffic.