what does this sound like? overheating.

yet another overheating thread. '92 jeep cherokee pioneer 4x4 with 4.0. we had a pretty big freeze recently with some snow and since then my jeep just hasn't been working right. i drive about 5 minutes to work and i can make it there, but by the time i arrive, i'm just getting into the red on my temp gauge. i turn it off and coolant/steam rush out the resivour cap. thermostat was replaced a month ago (preventive maintenance) and the water pump does not leak. have tried 3 different caps on the coolant tank, so i've eliminated that too. idling in my garage it takes 10 minutes to get into the red on the gauge. e-fan works. upper radiator hose is extremely hot, lower is cold. radiator never gets warm except where the upper hose meets it. not getting any flow through the radiator for one reason or another. radiator is in good condition, no visible leaks.

i'm thinking about having the radiator flushed, but i also wanted to verify another assumption. i'm assuming the water pump is ok since it does not leak. always heard that its not bad unless it leaks. true?

any other insight?

HuntMarsh said:

i'm assuming the water pump is ok since it does not leak. always heard that its not bad unless it leaks.

Click to expand...

not always a safe assumption-- the impeller can be bad/worn without leaking. It sounds as though either the radiator is completely stopped up or the H2O pump isn't moving any coolant through the system.

After you check the water pump take the tanks off the end of your rad. and inspect the tubes. Youd be surprised what kind of junk can clog up in there.

Resolve this problem ASAP or you're going to have bigger repair like a headgasket or a cylinder head. Overheats are tough on the engine.

I would suspect the water pump but also could be the radiator. Do you know how old both of these components are?

If they are old and you plan on keeping the vehicle, you might want to get into this and replace both of them. Not that big of a job really and then you know you're good to go with your cooling system (inspect/replace hoses as necessary)

Seems like you could take the bottom radiator hose off and pull the upper hose off the motor. Hold it up and run a garden hose into the open end of the top hose. See how the water flows through the radiator. If that is good, it's likely to be a shot water pump.

As said, WP or radiator is plugged, I would put my money on the radiator.

If the WP was frozen up, you would know it by the belt. A severely worn impeller will move some coolant so you should get some heat to the radiator and lower hose. Of course, if the impeller is off the shaft then you would also get the symptoms you reported.