Hello,

I have a 1997 Jeep Cherokee Sport stock
I was driving it pretty hard (high RPMs) in the snow the other day, and it started overheating, coolant was boiling and pouring off the reservoir. I waited for it to cool and added water to the system and it seemed to be fine. A few days later, the temperature started going up under heavy driving or traffic, so I would turn it off and wait for it to cool.
I did a radiator flush and it did not fix the problem, so I replaced all of the following one at a time and the problem still present:
1) Radiator cap
2) Thermostat
3) Fan clutch
4) Water pump
5) Catalytic converter
6) Coolant
The electric fan is working, and the radiator is fairly new, no signs of heater core leak, and yes, it cannot be the head gasket because: It doesn't lose coolant, it doesn't smoke, and the coolant doesn't mix with oil.

What could be the problem? I am running out of possibilities and tired of spending money.

 

It could be that the thermostat is still sticking. You can test it in by putting it in water on the stove to see if it opens and closes. Or maybe needs flushed again, sometimes a flush can loosen things up and clog the radiator.

 

Pop off your upper and lower hose from the radiator and use a hose to flush it from top to bottom and bottom to top. In other words, flush it like you'd flush a heater core. If you've replaced all the stuff listed, and are 100% certain your head and block are sound, you more than likely have a clogged up radiator.

 

Thank you all.
Replaced the radiator and removed the thermostat since it's almost summer. Problem solved, running at 180 degrees.

 

Check to see if the head gasket is bad. I had the same issues pulled the head and foun d out the gasket was bad took it to the machine shop had it milled. Heating issue gone.

 

Removing the Tstat will not buy you anything. The cts will tell the pcm that it's running under 190, and you will keep going in and out of closed loop. You will fail inspection because your monitors may not complete and it will not run optimally at all. Additionally, the Tstat is what keeps the temperature steady and even, without it you're all over the place. Which, might have been ok in my brother in law's '69 6 cylinder chevy pickup that we used to go out drinking in, but...not obd2.

 

+1 to 97 grand. In a weird manner, it can even make your Jeep run hotter in the summer. Reason is that without the t-stat to regulate coolant flow, your coolant never gets a chance to fully dissapate heat. When it closes off the loop, coolant sits in the res cooling off. When needed, it recycles that now cooled coolant into the engine, flushing back out the hot coolant, and processess repeats. Without that regulation, coolant does not spend enough time in the rad to cool, and slow movement (crawling, city driving) will cause it to gradually overheat. Best advice, make sure to get the correct t-stat and leave it in