Originally Posted by WingingIt74
I've been leaning towards the water pump, as maybe it's pumping but not pumping enough??? I do have a problem of wanting to upgrade instead of just fix, what's a good water pump to get?
Yes the Mishimoto was new and did come with a new cap, but it did not seal well, from what Auto Tire told me. Fluke it may be, but that part of it is fixed now with the new cap, as it does not leak now. I'm passed that point now, just need to figure out what is going on so I can drive it
As per usual, you are welcome to do as you wish, but I don't mess with what the Jeep engineers figured out so I only use OEM water pumps, thermostats, coolant, and radiators.
I fix rigs quite often with overheat issues and not once have I not been able to solve them with OEM parts. In this case though, I wouldn't have an issue with the radiator you picked as they seem to be fine.
That said, I just finished a rig with very similar symptoms. Drives fine, put it under load going up a hill or use the AC and the temp would spike, turn the heater on and it would come back down to normal.
Checked and replaced thermostat due to being unable to circulate coolant after the flush.
Checked and reinstalled water pump, did not replace because it was fine.
New coolant didn't help, still had the issue. Finally, the light bulb turned on and I recalled that the radiator drained slower than others I had done.
Against my better wishes, I purchased and installed a new OEM radiator and the rig now works perfectly. There was no external clue that the radiator was the problem except the slow drain.
Point being just because you have what appears to be a good radiator, don't rule it out.
BTW- the temp spike is because the gauge operates like a "gauge" until it exceeds the normal operating temp zone and then it will spike to let you know there is a problem which is also why it pops back into the "good" zone so readily. Gauge is operating as designed.