Cooling problem with Jeep Cherokee

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.

 

Drifter mentioned circulation problem,

also need to check that air is comming through the radiator it is not
clogged up with mud or bugs. Also make sure that the fins aren't corroded
and falling off the radiator. I have heard of rare cass where the fins on
the impeller of the water pump have broken, or the pump is about to seize.
Also make sure the belts are tight. If you have replaced the pump, there
have been cases where the pump was designed to rotate in the opposite
direction. If you have recently changed your accessory belt, make sure
that it is threaded in such a manner that the pump rotates the way it is
suppose to rotate

Wouldnj't hurt to perform a pressure test on the coolant system, but i
don't know if that is possible, does the radiator have a cap ?

Good Luck

 

You've changed the thermostat so assuming there's adequate coolant, no air
in the system etc ... maybe turn on the heater full blast which imo is a
quick and dirty check that there's coolant circulating. And if all seems ok,
then must be an electrical problem ... loose connection, temp sensor,
something like that.

 

Classic symptom of frozen radiator. Used to happen all the time before
everybody ran antifreeze all year. Are you sure yours is up to snuff for
low temps??