Hi! I'm new to the site honestly but have owned my cherokee for 2 years now and love it. recently on a trail ride while going up a long but not too steep hill (was in 4x4 high range about 2000 RPM for 15 minutes if it helps) and my temp went from the usual 200 it runs at and shot up to the red zone. i let it cool down and it was perfectly fine the rest of the day. just today i was on the highway and wasnt running it hard at all and it started over heating again so after letting it cool down and getting it home i flushed the entire cooling system out a few times with CLR (recommended by my father) and then 2 more times with pure water to be safe and then topped it off with antifreeze and water (50/50 mix). its still having issues with temperature. i drove it for about 20 minutes after topping off the antifreeze and everything and it was still over heating. the jeep is a 99 XJ 4.0 with about 245,000 miles on it. im concerned i have a bed head gasket but the jeep is running very strong yet and not miss firing so i dont think its that and it had good flow in the cooling system so im going to rule out water pump (although id rather it be that) any thoughts? im open to checking anything at this point cause i dont want to let the jeep go. also no antifreeze in the oil and the antifreeze didnt shoot out the radiator cap opening while it was running but i know that doesnt always mean anything. Please help

 

also my electric fan and my mechanical fan are both fully functional..

 

There's waaayyy more to cooling system maintenance than just flushing and refilling. Which list is shorter.......cooling system components that HAVE been replaced or HAVE NOT been replaced.

FWIW, the CLR web site says "do not use CLR in a automotive cooling system". Might want to pass that along to pops.

 

Have you removed the T-stat housing & looked at the t-stat? Water pump ever been changed? The impellers do wear down.

 

When in doubt change it out. Cooling system parts are very inexpensive for an XJ, so think about changing the radiator, water pump, thermostat, radiator cap, fan clutch, and all of the hoses. Look at the freeze plugs and make sure they are not showing signs of leaking or rotting out.

 

Yeah, praise yourself lucky you guys can get the parts cheap, like Busted mentioned.
Investing in cooling system maintenance is one of the best things you can do for your XJ.