its kind of long but bear with me. I was on my way home from work and out of the blue I heard a beep and watched my temp gage rocket to its peg, looking for a place to pull of I notice it returned to normalso keep going, when i got home I could hear the ratiator boiling so I felt the top hose it was on fire and hard as a rock and thebottom hose cool left it cool off took it for a ride and same thing so I changed the turmostat and un hooked the hoses and flushed it out a lot of rusty water came out. took it for a ride after all that and bam the temp gage went up to its peg again not slow but fast then back to normal, when I got home it was hot real hot and running rough and starting likr the battery was low. hoses were the same I was mad now pulled the thumostat and tested well it didnt open in a rolling boil on the stove, picked up another one tested it it open ok on the stove, I put it in and bam same thing. Madder now I pulled it out and just put it back to gether with out it and The same thing is happening top hose hot bottom cool same with the heater core top hot bottom cool. no smoke outr the back and oil is black, and there is not blowing heat inside. top hose does fill softer. amy one got any Ideas Help oh Its a 1999 cherokee 4.0

 

Maybe a bad water pump or faulty fan... If you had a cooling system pressure tester hook it up and dont put pressure on it start it and watch the gauge if it climbs fast you have a leak into the cooling system eathier by the head (cracked ) or bad head gasket....

 

If you start it up from a cold engine and let it sit there and idle a long time, will it overheat then, or, do you have to actually drive it for it to overheat?

If driving it under load is what causes it to overheat, you may have a clogged radiator. If the rad is clogged then the heater core is probably clogged too which would explain why there's no heat on the interior.

Also, a hot upper hose and a cooler lower hose would indicate lack of circulation through the radiator I.E. > clogged rad.

 

I agree with the radiator. Rusty water came out, but it may not have all come out. Could be clogged.

 

Thanks guys I was thinking the same now thar i have cooled down yes it will sit there and run for half anhour ideling and its fine but head down the road it over heats going to check it out now thanks again

 

Your radiator is clogged....

 

yup I just checked the fluid and its rust colored again

 

You'll probably just get mad again but you will be removing the entire dash to replace that heater core. Has the cooling system (or the vehicle) ever had any maintenance?

 

yea I figured I would have to pull the dash ive done it on several other cars in the past, as for maintance? probly not much before I got it in feb. It belonged to my wife and her ex and I did find out there was a leak in the radiator and he (the ex ) poured 4 or 5 bottles of bars leak in it. what an a## got my work cut out for me now thanks for the help i NEED ALL i CAN GET

 

Yea i agree your radiator has got to be clogged. I have been dealing with a similar issue on mine. going to be trying to flush the radiator soon. let us know how it goes.

 

Does any one know it you can open the plastic side off the radiator so it can be cleaned, with out braking it, this way you can see what is cloged up