For those of you curious as to why your Cherokee is overheating. Even with no signs of leaking at gasket, inlet tube, hoses, or weep hole, this still can be a problem. This is what happens to a water pump impeller after years of use, and last owner not flushing system out once in 14 years.

 

Makes me think of:

 

Owner neglect will kill anything.

 

DJB is holding out. He once posted a photo of one as flat as a dime...

 

Hahaha what a perfect video for it! And if using it as a slap chop doesn't work i could always take the impeller off and start using it as a ninja star.

 

Sorry for jump starting an old thread but I really hope my water pump does not look like this.
We bought a 2000 Cherokee sport this past summer. Two weeks ago the radiator split in 3 places, the "coolant" was orange / gold and glowed under a black light.
Radiator from DPG and new thermostat installed.
Still no heat.
Stat opens in a pot of water starting at 180 and fully open by 200.
Dash gauge stays at 210 and e fan comes on and stays running. Removed hoses to heater core and back flushed them.
Radiator flush and water in system released a bunch more of the orange / gold crap.
Should I replace the water pump also?

 

At least pull it off and inspect it. While its off, you can flush the block more thoroughly, too.

 

This will be fun in the 20 degree temps here in Michigan.

As for flushing the block more, would a rag around the garden hose end stuffed into the the thermostat opening be enough? I have already flushed the heater core through the hoses for it.

I have never worked on a 4.0L in line motor before. Some Ford but Mostly Chevy small block experience.

Thanks again for the help and the answers.

 

No, definitely not. If it's not overheating, I'd wait for warmer weather.

 

It could also be the heater control valve not switching from cold to hot. Look under the dash behind/near the controls on the passenger side. The flap should move freely when you rotate the ****.

 

Glowing coolant, huh? Radioactive.

Are both your heater hoses getting hot after the engine is at operating temp, and the heater is running?

 

Good example of what cavitation does when coolant is neglected.

 

Replace EVERYTHING, get a 195* stat instead of the 180, backflush heater core. Oh wait, you did that? Still no heat?

 

That impeller is not spinning fast enough, nor is coolant viscous enough to create any cavitation. Thats corrosion plain and simple. If cavitation was the case, the soft aluminum housing would be gone long before the stamped steel impeller.

The 4.0 can't spin fast enough to worry about cavitation.

 

Your mistaken...When coolant breaks down and turns corrosive it forms microscopic air bubbles which beat the hell out of the impeller. As a retired engineering person I can tell you this is called cavitation. But you are correct in saying it is from corrosion.....yes, corrosion caused erosion!