I just got my '99 Cherokee Classic after my mom just dumped $1200 into the cooling system & brakes, tune up, ect. (not sure what all was supposedly done yet, but it did travel 6hrs back to St. Louis w/out overheating at all) however just a week ago I was going to work (about 20-25mins drive) & it started over heating a little, got up to 220° then it jumped straight to 260°. So I got off the highway & let it cool down but then made it & back home just fine, it was a couple of days later when I had to return to work it did it again, then after work I had a hr drive to a friend's & it would not cool down for nothing, I was only 10mins away when it was just below the red when it went into 260° & the belt popped off about .5 miles away so I kept going, got the belt back on but ever since then it won't run cool!
I replaced the thermostat with a 180° & new gasket + the new belt & will change the temp sensor today!
​​​ I will ask my mom after work about what all work she had done, but I did notice that the electric fan won't stay on for long, it'll turn on for a minute (maybe before it cuts off again! Any ideas?

 

Wrong section.
mods please move

 

Moved. Thanks TT

 

You need a 195 Thermostat. I would go with a mopar one, at the advice of Cruiser54.

Secondly, make sure your coolant is completely full.

Yes, it will help to know what all was done to it because the cooling system boils down to (pun haha) only about 9 things.

1. Radiator Cap (get a Stant 10230 or dealer one if at all possible)
2. Radiator (clean as you can get it or a new one. Sometimes they have hairline crack leaks that you can never see but when at Temp it allows overheating)
3. Hoses (no holes or plugs, this includes the little overflow hose. I'd say flush everything forward and back. Jeep off and Jeep on if a radiator cap doesn't fix it. Because at that point you'll have stuff off anyway. Search "Flush CherokeeForum" on Google and you'll see many threads)
4. Water pump (if old, it may not pump water correctly)
5. Thermostat (get a 195 Mopar if at all possible)
6. Heater Core (a clogged one will not cause an overheat alone but it can send junk into the radiator or T-Stat housing and clog things. Again a flush can help or fix it).
7. The E-fan (it only kicks on when the Jeep reaches a certain temperature and then kicks back off at 210 or 212. It also runs with the AC on. Many guy put theirs on a toggle switch. I did. But it only kicking on and running for a minute or two is normal)
8. The Clutch fan (helps keep you cool at slower speeds, such as traffic, stop and go)
9. FULL COOLANT. Make sure heat is on when filling. Let Jeep heat all the way up with Radiator cap off and wait for it suck water down and repeating until you know it is 100% full.
​​​​​EXTRAS
And 10)
Some guys say the fan shroud helps direct air through the radiator. Many guys have it missing and run perfect Temps.
​And 11) The Temp gauge/sensor. Some guys report theirs was reading wrong the entire time and they were never hot. Have to check with a temp gun to know this.
And 12) Blown Head gasket can cause overheating.

I think that covers all the cooling system. If not somebody will chime in. Also try to never let the Jeep overheat. I've always cut mine off before it reached the red. I usually do if it reaches that last white line because at that point I know it's about to overheat. This can usually always save you from having a blown head gasket/cracked head situation.

Good luck and ask any questions, even if you think it's dumb question. These dudes like to help.