Hi XJ's Team
I need serious help about this topic that we discussed over and over but I still need big help after Changing Clutch Fan (Mopar), Thermostat (195 Mopar), hoses(mopar), Waterpump (Flowkooler), Radiator Mishimoto, front sensor and OE Electric fan works fine but as I go up hilll it begins to overheat and Check engine light comes on, Mechnic did comprassion test on Spark plugs I got 140 each.

If you know a Mechanic can help me or any ideas would be much appreciated.

Thanks,
Ed

Do you have both fan shrouds intact? Also, when it's hot, does the mechanical fan rev up and make an obvious roaring sound to indicate it's working?

Yes, Both Shrouds are there and I replaced the Fan clutch with OEM Mopar, It spins but as RPM goes higher it slow down the spinning, I never noticed fan clutch engages as engine warm up.
Thanks for reply,

Is this an open loop system or closed loop? OR does your jeep fill from a surge tank on the passenger firewall or from a spout off the radiator on the driverside?

Regardless, these jeep can be common for trapping air pockets and giving owners headaches for resolving the hot pockets they bring on.

If you have the system with the fill spout off the drivers side of the radiator - invest in a spill proof raditator funnel


this is purely just a cheap example but if indeed you are fighting air pockets - this is a good solution.

otherwise a simple Digital IR thermometer wouldn't be bad either. While on its hot climb, stop- pop the hood and temp check the various areas of your cooling system and hoses and compare them to your gauge reading

Well, that's not good. Here's how a property functioing fan clutch should behave when the engine is hot.

I'll do this burp next because I tried first to run the engine with driver side lifted on up hill.

Thanks

Another thing that can help with the air pocket problem is, with the engine not running, take the temperature sensor out of the thermostat housing and add coolant at the radiator until it comes out the hole where the sensor lives..
( If coolant pours out when you take the sensor out there wasn't an air pocket there)

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It should also do that cold for the first couple miles until the fluid is spun out of the inner part of the fan.

I had an overheat problem on my '99 a few years ago on a 2000 mile trip, I had replaced the water pump, t-stat, and hoses before the trip. Had overheat problems as you describe, went through everything trying to figure it out, turned out I replaced the water pump with a high volume one, the new lower radiator hose did NOT come with a coil spring inside it like the factory one and when I would rev the motor the high volume of the pump would collapse the lower hose and restrict coolant flow. I could rev the engine and visually see the house suck together. Hit Bakersfield NAPA and go another hose with a spring installed and had a pleasant drive home.

Check the lower hose because with the high volume water pump it may be the problem...

Battery is New too.

I've already replaced it with Mopar with spring hose ($70)