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Unread 04-19-2005, 03:04 PM   #1
motorheadmach1
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1990 XJ Cherokee 
 
Join Date: Feb 2005
Location: UNION CITY, TN
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whys my jeep overheating?

befor i go to all the trouble of replacing thermostats and flushing the cooling system, are there any normal problems that make a 4.0 with an automatic overheat on a random basis. for example i drive my 30 miles to work this morning and had no problem i drove home and the coolant was boiling.i can drive all day in the bud and not have a problem, i got stuck once and tried rocking myself out and the coolant was boiling again. any ideas?

thanks, andrew

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Unread 04-19-2005, 04:39 PM   #2
bockwho
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well lets start here .. many if not all will agree that heat will be the death of your 4.0 L

next we need to know what you have done to your coolant system how fresh is your anti frezze what kind of watter you put in you system. how your system is set up. are their any leaks is it toped off did you burp it if using the closed system but I am will to bet that one of your problems are below 1,2,3,

also if you turn you heater on will it cool back off. this is something people over look if you car is starting to overheat roll down the windows and crank the heat up .. its a extra radiator. Ive used it to get home when the temp started creaping it gets it to drop back down.

Im sure someone will fight me on this but I always use distilled water. 89 cents a gallon or you can distill it yourself. I do it and our water is good people with heavy deposits should only put distilled water in the rad.

1. when was the last time the rad was changed what type of radiator
a) if it needs to be changed spend the extra 75 bucks and do the open system conversion
b) make sure you get a 3 core all metal radiator

2. Is your bottle cracked?
a) the way the this system work is by building pressure which raises the boiling point of the cooliant. try it on your stove with regular water.
b) save the money on the bottle and put it twards the open system
c) give you old bottle to some other mj or xj smuck who has not coverted his or her system

3. Is you fan working?
a) set up a switch if need be I made a jumper to replace the relay and when the seasons change I would simply go out and plug in the jumper and any time the car was on the fan would be on. you could also do this with a switch.
b) you can also set up dual fans with a little more work and maybe see a slight hp gain by saving your engine from spinning up the fan.

Im sure someone here knows where a write up is on the conversion this is alot of info if you have any specific questions pm me also search in the xj forum its the same system
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Unread 04-19-2005, 04:40 PM   #3
MJDriver
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Something blocking in the water pump or thermostat will cause that. I would replace the thermostat and go over the pump top to bottom to make sure it isn't leaking.

Replacing the pump with factory parts will run about $140 after pump, coolant and thermostat. Its cheap insurance against a whole new engine.
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Unread 04-19-2005, 08:41 PM   #4
motorheadmach1
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ok heres what i have i just bought the truck a month ago dont know much about the coolant although it is still green, it is a closed system yes i hate it too! and there are no cracks or leaks. i dont have gauges i have idiot lights i dont even knwo if the temp sensor works because the idiot light didnt light. i didnt know you could convert it to an open system, how hard is it? i have a new water pump just havent installed it dont know the old one to be bad i jsut bought it because it was cheap and ill need it one day. doesnt sound like theres anythign common to the jeepster overheating other than everyone thinks the closed system sucks, and also how do i burp the closed system i didnt see any bleed valves.
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Unread 04-20-2005, 04:54 AM   #5
Ndru
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The conversion to open is very easy, you'll be doing all the fork already if you change your water pump. they have the GDI 3core at Advance auto parts for about 130 . there are many write ups on this on various sites. basically all you need is a new overflow bottle and the radiator. I'd go to a scrap yard for that .
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Unread 04-20-2005, 01:43 PM   #6
bockwho
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what you need to do is make sure you bottle is tight make sure the cap is on tight

to burp .. you need to leave the cap cracked so it vents to the outside fire it up and let it or drive to the store and back with it cracked open. unless you have a heck of a air bubble in it ie system just refilled then this is probly not your problem

the open system is very easy .. andrew just did it when I owned the mj I had collected most of the parts over the years. In antispation of the cracked bottle or the wasted radiator. sure enuf the bottle cracked ..

the bottle can have a pin hole in it and it is bad. look on the bottom

here is a cherokee america site so a google search this is a comon conversion

http://www.off-road.com/jeep/cheroke.../radiator.html


You can also find you temp bulb on a 4.0L on the aft drivers side of the head it should have a purple wire on it. Im also not sure if the it10t light works if you have guages installed.

I want to ndrew to convert his MJ (my old MJ) to all electric fan but but thats down the road.

Kelsey
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Unread 04-21-2005, 05:31 AM   #7
Ndru
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yeah, converting to all electric fans is about the last thing on a long list. shoot, we have a bunch of parts already just a matter of putting it all together...
As for cooling, since I replaced the radiator I had to disconnect the electric fan ( that was hard wired for constant) because it would never get to opr. temp I expect that in the summer months I'll have to hook it back up . I believe I have the overheating thing fixed
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[COLOR=DarkRed]88 MJ Eliminator [/COLOR] 4.0 AW4 / Rusty's intake, borla header and muflr, convrtd. to open 3- core
[COLOR=Navy] 00 XJ Sport [/COLOR] 4.0 Aw4/231 , STOCK
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Unread 04-21-2005, 06:20 AM   #8
cj7xjmj
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If it is only overheating at slow speeds it means your clutch fan is gone. The way to check this is when you turn it off the cooling fan should stop with in a turn or two. If it doesnt, your clutch fan is gone. I am still running the closed system, and I have had zero problems caused by the setup. Having it packed with mud is the only time it got hot. Call me a smuck.. but if it isnt broke, dont fix it




Patrick
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Unread 04-21-2005, 03:17 PM   #9
MJDriver
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Since I am seriously considering swapping to an open system, can anyone recommend a good tranny cooler to add with my new 3-core radiator I will be purchasing?
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Unread 04-22-2005, 09:42 PM   #10
bockwho
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correct me if im wrong ndrew but if that 3 core you bought should of had a trans cooler in it.

KB
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Unread 04-23-2005, 05:24 AM   #11
Ndru
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Quote:
Originally Posted by bockwho
correct me if im wrong ndrew but if that 3 core you bought should of had a trans cooler in it.

KB
Kelsey...either call me Andy or spell the screen name right hahaha

But to ansrew your question , YES it has an internal Tranny cooler. Good luck getting those clips off that hold the lines on. it's tricky.
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[COLOR=Navy]97 TJ Sport [/COLOR] 4.0 5spd 4" pro comp lift 2"BL w/ 33's, k&n, poweraid spacer, dynamax
[COLOR=DarkRed]88 MJ Eliminator [/COLOR] 4.0 AW4 / Rusty's intake, borla header and muflr, convrtd. to open 3- core
[COLOR=Navy] 00 XJ Sport [/COLOR] 4.0 Aw4/231 , STOCK
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Unread 04-28-2005, 09:22 AM   #12
Francisco Gomez
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Quote:
Originally Posted by bockwho
3. Is you fan working?
a) set up a switch if need be I made a jumper to replace the relay and when the seasons change I would simply go out and plug in the jumper and any time the car was on the fan would be on. you could also do this with a switch.
b) you can also set up dual fans with a little more work and maybe see a slight hp gain by saving your engine from spinning up the fan.

I installed an electric fan with a manual switch. I just got used on starting the engine and the fan at the same time. Same as turn off. For me it has been the best. And when I go into deep water, I just turn off the electric one.
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Unread 07-16-2008, 08:16 PM   #13
Rubycon7
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my rubicon 06 is over heating and about the same time it started over heating, i found a leak from some random black tube right under the passenger side seat which made a small water puddle for a few days and now seems to be empty of water. since its empty my jeep over heats very easily. is it my radiator hose or water pump or what?
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Unread 07-17-2008, 09:03 AM   #14
maddzz
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If you are overheating and you have water on the floor on your passenger side your heater core is probally leaking and/or bad. But that should be up under your dash. The water is probally runing down and causing the puddle, seeif the carpet is wet up under the dash on your passenger side.
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Unread 10-06-2013, 07:42 PM   #15
Kaivic2010
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Tried burping my cherokee but still overheating

I need help I have 89 cherokee new radiator just got jeep, it's overheating I have changed thermostat , installed a 92 thermostat housing with radiator peacock to burp but just steam comes out no fluid it's filed like its supposed to be
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