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Coolant Issue

653 Views 0 Replies 1 Participant Last post by  NotWard
Hello this is my first post here and it’s with a problem that I’ve been fighting for a few days now.

Jeep: 2006 tj (duh) 2.4L I4

Alright, initially the Jeep got a check engine light (P0128) but there didn’t seem to be any spike in engine temp or loss but something had to trigger it. Figured ok I’ll replace the thermostat and coolant sensor.

Got a new sensor and a motorad thermostat. Drained, flushed, and put in the new parts. Bled the radiator but I couldn’t get up to my previous normal temperature which had been 200~ degrees Fahrenheit, and instead was sitting 170~. Thought ok maybe the thermostat came bad and is stuck open or the gasket on it had seemed a little weird and maybe coolant is getting through. Even checked the temp with an obd scanner and was matching my temperature gauge. Then I drained the coolant out, got the thermostat and it was fine, although the gasket was a little gnarled up.

With this in mind I wasn’t sure why I wasn’t getting up to normal temp as I do have limited knowledge and this work is new to me.

Went ahead and got a mopar thermostat because oem should be a straight shot. Got the thermostat, drained the coolant, put it in, and proceeded to bleed the radiator. And was hanging out at 196 degrees no problem.

Imagine my surprise when I woke up this morning and the Jeep couldn’t get above 174 degrees. I’m honestly at a loss here and am not sure where the mistake I made or thing I didn’t check is at.

When turned on later the engine did idle at around 203, but when driving would go back down to 170~ degrees. As I write this I attempted to bleed the radiator again because why not but couldn’t get the engine to idle above 176.

Of course I am eager for anyone’s insight as to the solving of my problem and would greatly appreciate it, thank you for your time and possible fixes, and have a wonderful thanksgiving as well 🙂.