Hey, I want to say I've been reading these forums for the past few days. Its been very helpful in this awesome problem i have. But I haven't been able to fix the issue. this may be a long story. Keep in mind I know little about vehicles and I own a 2000 Jeep Cherokee Sport with the 4.0 inline 6. Its got 240,000 miles on it and I'm the second owner.

The issue: Its over heating and has stalled twice.

How the problem comes up: it started about 6 months ago when I was in Ft. McCoy wisconsin driving some back trails. I drove up a very steep hill and after my check gauge light came on and the temperture was one dash Higher then 210. I found I had low coolant so I bought some and added it. the problem didnt raise again for at least 2 months. When it started up again I was losing Coolant but there was NO leaks to be seen. It would drive fine and have no issues I could notice except for when I would get off the high way and stop the check gauge light would come on but the temp would read 210. No higher. It did that for a few months til early sept. Then in sept it would raise to 210 hold there for awhile then would jump to 250 and the check gauge would light and the alarm would buzz. after a while it would drop down to 210 again and not have the issue. that was a once and a while thing. Maybe once every 10 days. Mind you I drive the exact same route to and from work. so change of distance wasnt it. about a week ago it started to heat to that point every time I drove it. it would heat to 210. then to the next hash mark(guessing 220). then jump to 250 sometimes 260. each time It did this I would put some coolant in. When I put it in I noticed it was badly plugged with rust junk. and my coolant was a DARK poo brown.

What I did to try and fix it: I flushed the system, replaced the thermostat, changed the spark plugs(didnt think it had anything to do with it but figured it wasnt going to hurt and it was probably for the better).

Still getting the issues so I purged the system to get the extra air out because I figured that was the problem. Ive done this twice per forums here and a local mechanic telling me to do the same...no luck. I thought I had it fixed so I drove it around and it stalled coming off the highway spraying coolant all over the engine from what looks to be the Thermostat housing. possibly the gasket or the Coolant Temperture sensor. after that my check engine light came on. drove it over to Advanced auto and the ran the check on it. Said it was the THrottle postion control sensor. Replaced that. Now the idle is perfect but still over heating. when the Jeep over heats the over flow begins to pour out coolant in a water fall fashion. It happened at the auto shop so I replaced the Radiatior cap. that didnt fix the issues. I filled the engine with coolant per the manual. It seems like all of the coolant in the radiator is being dumped into the overflow and its not pumping new coolant in.

I'm not burning coolant, nor is there any visible leaks, or anything in my oil.
the fans kick on and seem to work right. The only sensor I havent replaced that I think might be the issue is the coolant temp sensor. when I run it and unplug the coolant temp sen. the temp goes down quite a bit. I plug it back in and it goes up again...when its unplugged it seems to still be reading temp.

HELP HELP HELP!

 

What cooling system maintenance/replacement have u done? Telling us that shortens the guessing list.

 

i've replaced the thermostat, flushed the system, and replaced the coolant. Tried twice to burp it.

 

How old is the radiator, water pump, fan clutch, rad cap, hoses, etc.

 

I don't know. Im the second owner.like I said radiator was gunked with rust

 

with the engine completely cold, take the radiator cap off, start it up and then give it a few revs to see if any coolant bubbles out or gushes out.

use the throttle plate linkage to rev it so u can get a good look at it..& dont stick your head over the open rad cap...

you stated the jeep was spraying coolant from what appeared to be the t-stat gasket/housing.. i assume you've fixed that of course.

also, a bad coolant temp sensor wont cause the engine to actually overheat, it just causes the temp gauge to malfunction. it can also make the jeep stall if it for any reason is reading too high a temp, whether its a true reading or false reading.

 

I just ran it. Ill have to wait a while. Ill post on here when I do it. I've ran it with the cap off and its bubbled out. But I didn't give it any gas. Just idle.

 

My guess is.......some or all of what u have not replaced. If u want it to be reliable, u've got to do the maintenance. Presume the PO did nothing.

 

this test u gotta do with the engine completely cold.. so wait about a few hours.

 

Im no mechanic so this might be something ill have to bring in. And I've put most of my moneyinto just those hand full of parts. So hoses water pump and radiator would more then likely need to be replaced. Awesome.

 

.......and fan clutch and rad cap.

 

I started it a reved the engine and no bubbles. completely cold.

 

If the coolant was that bad you may have a plugged radiator. One more thing check the pulley on the water pump and see if it feels loose. I had the water pump shaft on my chevy snap.