Jeeps have really crappie sensors, especially the temperature one. I
would check the connections on it first, then replace it before doing
any rad work. If it 'really' was in the red, you would feel it....

The sensor is on the top of the head on the back drivers side corner and
has a purple wire going to it.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Ed wrote:
>
> Vehicle is a 2001 Cherokke, 4.0
>
> Problem: I start the vehicle and bring it up to operating temperature (gauge
> reads between 190/210). Heat in vehicle works fine.
>
> On two occasions I was driving along when a warning chime sounded and the "Check
> Gauges" light came on (I had been driving for roughly a half hour...outside
> temperature was in the 20's). I looked at the temperature gauge and it had shot
> up all the way into the red zone (260). The first time it happened I pulled
> over, shut the engine off, and checked under the hood. I didn't notice or feel
> anything that would indicate the engine over heating... no excessive heat,
> steam, odor, or "pinging". I restarted the vehicle and the gauge dropped back to
> 210.
>
> A couple of days later, it happened again; only this time the "check gauges"
> light turned off and the gauge dropped back to 210 before I had a chance to pull
> over (fortunately this time it happened I was about 100' from my driveway).
> Again, no observable symptoms of excessive overheating.
>
> Once I was able to check things more closely, I noticed that the upper and lower
> radiator hoses were warm to the touch, and there was no pressure and very little
> coolant in it. The radiator and cap were just barely warm.
>
> There's no sign of any fluid leaks or lost coolant. The level in the expansion
> tank hasn't gone up or down. The electric fan has kicked in a couple of times,
> but the gauge was still in the safe zone (about 230).
>
> I replaced the thermostat (195), and it's still running the same way... engine
> warms up, heat is fine, but radiator, upper and lower hoses are barely warm.
>
> What could be the problem here? Weak water pump? Clogged or blocked hoses and/or
> radiator?
>
> FWIW, the outside temperatures here have been in the low/mid twenties.