after almost replacing everything . i did research and found a short page of solutions to this common jeep prob. and all of them had to do with the plastic filler bottle cap. if it leaks it will not circulate the water. i could not see mine leaking at all after staring at it for quite a while. so i thought this isn't my problem, so i carried on with my tools. at the end of the day and no luck, i took my blue latex gloves off and put one of them on the bottle inlet then screwed the cap on. and everything started working .heater blows hot , no bogging out , and the main thing was the water started circulating almost emediatly. i was so happy and so pissed from all the work i did for nothing. the glove will break down like it is supposed to do so dont leave it on long. just long enough to see if it makes a difference. good luck

 

i know this bottle was only on the older jeeps so it is possible that your radiator cap or something up high that would let off just enough steam (that you cannot see with the naked eye) but it has to be up high or you would see fluid leaking. the jeep shuts down from overheating before the prob reveals itself. after the glove broke down and it went back to overheating i tried a piece of saran wrap and it works and prob wont break down as fast. i am not an expert on this subject , but this could be whats happening to your jeep in some sort of way. i will keep you posted even if this blows up in my face. good luck

 

Why not just get a new cap or replace the bottle?

 

i did replace it . i just couldnt beleive it was that and replaced everything else and still refused to mess with that bottle and cap which was the easiest of all the cooling components. they just appeared fine. anyway gotta go.cath u later thanks