Hey guy's, so I have a 1997 jeep Cherokee sport, 4.0 I6. I've been having a problem with it overheating af drive-through's and at idle after driving, at first I figured it just needed some coolant so I drained it all and sprayed some water through it then filled it back up, few days later it did it again. Then I replaced the water pump and thermostat, nothing, then I replaced the fan clutch and nothing. So finally I just went ahead and replaced the radiator, and it worked! It worked great for about 4/5 months and then one day I was getting air in my tires while it was running and by the time I got back in it was way over 210. So I was hoping it was just a bad thermostat so I replaced it again and nothing. Since then I've replaced the thermostat with a 180, changed the electric fan relay and temp sensor for the fan and it's still not working. Both the coolant and the oil aren't mixed and the engine sounds great running, I can't figure it out for the life of me, now the electric fan doesn't come on at all unless I put the ac on, even with the new relay and sensor but it overheats with or without the ac on so that can't be the only issue. Does anyone have any suggestions?? I'm desperate at this point.

 

What kind of radiator and what Temps are you driving in? Does it boil over or is it just the temp gauge reading high? I'd you have a temp gun shoot the thermostat to compare with the gauge.

 

It's a spectra radiator, and it stays a little under 210 while driving and then when I sit still it starts steadily increasing. The few times that it actually fully overheated and the check gauges light came on it was very hot. I could hear the coolant bubbling in the overflow.

 

You should really be checking temps with a scan gauge or an IR thermometer like the previous post suggested. Usually when you run hot at idle it's the fan clutch. I know you already said you replaced it; is it still working properly?

 

Fan clutch.

 

i second the clutch however could a bad fan shroud be culprit as well? one failing part of the cooling system goes a long way.

OP is the electric fan itself running ok?
if the relay is good and the fan clutch or electric fan is bad your engine will still rise in temp. junk clutches can good out rather soon but there are good replacements and upgrades like a zj fan clutch, or oem, but dont go AZ.

 

I have an obdii sensor I've checked the temp with and it's consistent with the gauge. I suppose I can throw in a new fan clutch again when I get the money, I'll report back if it works or doesn't, thanks for the suggestions!

 

Put in a new fan clutch and still doing it. I can't think of what else it could be, when I. Bolted the fan blades to the clutch there was a stamp reading "front" I assumed this meant that Side should face the front of the vehicle, could I of put it on backwards?

 

Is it possible your Radiator hose is collapsing due to lack of a hose spring?

-Jon

 

It was boiling the first time. Is that before you replaced stuff?

What's the temp when it's overheating now?

I've said this many times. When I got one of my 98's there was no clutch fan on it, the radiator leaked and the water pump was so shot it was knocking. Ran for almost a year that way. Never overheated. It would start to get hot and the electric fan would kick on and drop it below 210.

Finally changed water pump, thermostat and housing, hoses, coolant temp sensor and flushed everything a couple times. Installed a non leaking radiator from my 99 and installed a clutch fan from another 98 I picked up for parts.

Now it barely ever reaches 210. Also not running a shroud. So I don't know if my case is unusual but I don't believe a clutch fan or shroud are definitely needed. Of coarse there should be a clutch fan just so the electric won't cycle so much and in case the electric fails. But as long as the electric is working properly, the clutch in the fan or a missing shroud shouldn't cause overheating.

 

And please don't start the argument of the spring in the hose. Lol.

 

LOL!!!

Just a thought. I would probably look into the Temperature Sensor and Electric fan further (Even though the Temp Sensor and Fan Relay was already replaced) and test the wiring with a multimeter to ensure the wiring is good.

After my XJ is running idle for a while, the Electric Fan will kick on for a couple minutes and then kick off (Without the AC on).

Hope this helps!

-Jon

 

I hate just throwing parts at a problem; but you did say it ran fine for 4/5 months with the new radiator. Without knowing the history of the Jeep, could there be gunk build up in the block and it took 4/5 months for it to start clogging up the radiator? Did someone use stop leak at some point? also did you add 50/50 to it?

 

I've never put and stop leak or anything in there. I suppose it's possible though. I'll try hardwiring the electric fan to a switch in the cab and see if that does anything. Still blows my mind that tiny fan makes any difference.

 

I was kinda thinking the same. Might be gunk in the Heater Core as well. That can be easily bypassed though. I would grab the ole garden hose and give her a quick flush. Should only cost you a new thermostat gasket and/or some blue RTV, depending on how you wanna seal up the thermostat housing after the block flush.

However, you should be able to see at least 'some' gunk come out of the radiator if you do a quick flush on that to confirm gunk build up is the issue before flushing the block.

Hope this helps!

-Jon