Help! IT WON'T STOP OVERHEATING

[hotnboderd]

XJ,
Thanks for the welcome and reply. What's the easiest and cheapest way to check the fan clutch? I replaced the radiator cap and had it flushed a couple of weeks ago (added new coolant). I was going to replace the thermostat because it's never been replaced and because I figured that was the least expensive thing to do after the radiator cap. Thanks for your suggestions.
DQ

 

[XJNick]

Checking the fan clutch is easy:

with the Jeep off and the engine COLD, try turning the fan by hand. It should spin freely (no resistance)

Now turn on the Jeep and let it run to normal operating Temp., then:

with the Jeep off and the engine HOT, try turning the fan by hand. It should NOT spin freely (some to alot of resistance depending on engine Temp.)

If your clutch fan doesn't act like described above, it's time for a new fan clutch :mrgreen:

-Nick :!:

 

[hotnboderd]

Just a word of Thanks

XJ,
Thanks for the tip. I tried it just now, and there was resistance (it's hot). I'll try it in the morning, after it's cooled, for part two. I was rolling down the road at 11pm (in Tucson) and chuckling at how it still runs at 210, when the display tells me the coolant sensor is out. Yippee! (sarcasm). What does this mean with respect to the thermostat and is it still okay to drive the thing without worry of overheating? Damn! I'm gonna have to buy a chilton's as soon as I get some $$$ Any ideas? Thanks,
DQ

 

[MudderChuck]

Don´t know about the 93, some models had seperate senders for the temp. gauge and the computer. Some I´ve been told, are a combination unit (two in one).
Mine is on the left of the motor, under the exhaust manifold, towards the front of the motor on the block. Cables ran pretty close to the exhaust manifold (since have been rerouted) and looked to be rubbing in various spots. Worth a look.
If it´s the sender, that tells the computer the motor is at operating temp. It will possibly, kick the computer into warm up or trouble mode.
www.Alldata.com has really helped me, find and understand some of the sensor locations and function (in my early XJ). A subscription costs less, than an hours shop time, at the stealership. Probably worth it, just to know where all the lightbulbs are located.

 

[XJNick]

What display would you be referring to? On a scanner? On the dash??

My XJ does have two seperate coolant temp sensors, so maybe yours does too. If so, it won't effect the engine if the sensor for the gauge is out :mrgreen:

-Nick :!:

 

[Cherokee_MZ]

what size tires on standard rims?

cherokees have smal carburators so try putting in a bigger one!!

 

[hotnboderd]

Warn Winch Raffle with accessory kit

Thanks for the speedy reply chaps! My older boy has been driving it lately, and it hasn't blown up, so I'm guessing it's not a vital mechanism. Still, when I get paid, I'll buy the Chilton's book and then surf over to Alldata :idea: I'll check in with y'all to let you know what I find out.

 

[hotnboderd]

Just checking to see if my avatar pops up!? :roll:

 

[limbmkr]

Did you take the top radiator hose barely off but let the air out on top while you pour antifreeze into Resevior tank.. til antifreeze start to come out then quickly put it back in and clamp em down.

I had alot of problems with overheating after flushing and replacing new thermostat and all that.. One guy suggest to pull off the top radiator hose barely off i mean bottom part in but top part out and stick a screw drivers on top to let the air out as you pour fluid in the holding tank..

Hope you get that sucker worked out.

 

[sparkyshotrods25]

DID YOU TRY A NEW RADIATOR CAP?THERE IS NO WAY IT COULD BYPASS THE RADIATOR,IT GO'S FROM BLOCK TO RADIATOR TO BLOCK RADIATON.IN A CYCLE.ARE A FEW THINGS YOU SHOULD CHECK,IF THERE IS WATER IN THE OIL OIL IN THE WATER,BUBBLES IN THE RADIATOR WHILE THE RADIATOR CAP IS OFF, THESE ARE ALL SIGNS OF CRACKED HEADS AND OR THE BLOCK.IF YOUR ANTIFREEZE KEEPS GETTING PUSHED INTO THE OVERFLOW ,AND THE COOLANT IN THE RADIATOR IS LOW YOU HAVE A COMPRESSION LEAVE BEETWEEN THE WATERJACK AND CYLINDER.YOU MIGHT WANT TO CHECK THE COMPRESSION AND CYLINDERS TO SEE THE PSI AND IF THERE IS ANYTHING ADNORNAL IN THEM.

 

[radjcw]

On another site, now lost, I found an old Jeep mechanic's advice: You MUST 'Burp' the cooling system on the 4.0L Jeep engine by removing the temperature sender and allowing all the air in the head to be expelled. Do this by: 1) Jacking up the left rear as far as you can, which raises the temp sender. 2) Remove the sensing wire from the sender, which is on the top of the head at the left rear (Seen from the Driver's seat) of the head. 3) Use a 13mm Deep-well socket to remove the sender, and fill the coolant tank with coolant. Air will come out of the sender hole. When air stops coming out, and coolant comes out, replace the sender and wire, and top off the coolant. I've done this and at last it works!!! 88 Cherokee laredo 200k miles.