1990 jeep cherokee overheating and overflow?

change your thermostat. $6 part. easy fix. located at the front of the head behind two radiator hoses. one larger than the other. should be 3 screws on the housing. there is a gasket holding it on. so it may not fall right off. good luck

i changed that out as soon as the problem started. i cant figure out why its still acting up

well, beats me then. id try asking these guys. http://www.jeepforum.com/forum/f11/

could also be somehow your top hose is clogged or radiator is clogged up to and its just spitting everything into the overflow.

You might want to check and see if your radiator fan is working I have a 2003 Cherokee which had a problem over heating and first it was the relay and then the cooling fan blew a few times.

i agree. it could be an issue with the cooling fan. buuuuuut a 1990 has a belt driven fan. so thats not it. and not to be mean but could you have meant an 03 grand cherokee or wj? the xj was produced from '84 to '01

Yes I did mean a grand Cherokee but what does it matter if you look at most of the question here all or most of your grand or other wise,have over heating problems.

yes, late model grand cherokees have overheating issues. mine did as well, but a 1990 xj has an entirely different cooling system.

if the car(ie any car made in the worl that is an internal combustion) is flat out pucking coolant after only a short amount of time running it most likely is a bad head gasket. what happens is the gasket goes bad and can't hold in all of the pressure in the cylinder(s) and that pressure forces its way into the other systems that the head gasket is designed to keep separated. most of the time that means that it over pressurizes the cooling system before the car getts a chance to really warm up and the coolent gets forced out of the radiator/reservoir cap. I've seen this many times. Yes this means you're gonna have to take the head of and replace the gasket and the head bolts. but you shouldn't have this problem afterwards. Another good Idea would be to replace the water pump while you are doing this and flush the coolant system before getting started since you probably have a good amount off miles on the engine and all you do is dump a flush additive into the radiator and let it run before draining the entire system. Good luck

had same problem change the cap on the overflow tank also check tank for crack. check that the cap is tight

Make sure you have Burped the coolant... If there is an air pocket with this cooling system, it'll overheat.. Google burping a Jeep..

Top 3 possibilities) 1)STILL a bad thermostat -- if you really want to test put it in boiling water.... 2) check FLOW through system - pull radiator cap - let heatup for about 4 minutes - look to see if radiator fluid is FLOWING by looking at it --OR WITH CAP ON-feel for pressure in radiator HOSE. 3)go to AutoParts store, and do a pressure test on radiator system - pumping up to 15 lbs, and see if it holds pressure(do only when cold)... -- A BIG PART people miss is figuiring out what the problem is, before TRYING TO FIX IT.

its your head gasket. you will need the gasket replaced the waterpump and the thermostat. all 3 its a rule.

Some other forums suggest you may just need a new radiator cap - the springs get worn and so don't keep the pressure in the system correctly.