so i decided to flush the cooling system on my cherokee the other day because it was taking a while for the heater to get hot. it never ran hot and seemed to get to operating temperature normally, so i figured there was just gunk in the heater core.

so i back flushed the system and the coolant looked like coffee. put in new coolant and made sure there were no air bubbles in it. took it for a test drive and it would not get hot at all, didnt seem to get over like 150.

i figured i froze the thermostat open some how so i went and got a new one, took off the water outlet, which was cracked where the bottom bolt goes in, and there was no thermostat in there at all. put the new one in and changed the recovery tank cap and all is perfect.

how did it run correctly before the flush without a thermostat?!?!?!?! it warmed up correctly and ran at the right temperature and everything.

 

Mine was the same way. I hadn't had heat in a while and did some research. People said it might be the thermostat and since it was cheap and simple I went for it. Pulled off the housing and there wasn't one there!

Needless to say it heats plenty now!

 

all the junk was probably restricting the water flow enough for it to get hot. Thats probably a good sign it wont heat up now

 

thats kinda what i was thinking. ive only had the jeep a few months now and im glad i changed the coolant, one hard freeze away from a cracked block or radiator