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Overheating with A/C on / e-fan issues

TylerA23

NAXJA Forum User
Location
Greer, SC
Last week I turned on the A/C and a short time later the dash light came on and I saw I was overheating (almost pegged out). I switched the heat on and continued home. Temp went down drastically. Later, I tried the a/c again to see if it was just a fluke. Same result. Overheated. Got home and the coolant in the overflow reservoir was bubbling. Very hot.

Yesterday I popped the hood and turned on the jeep. Turned on the a/c and low and behold the drivers side fan (e-fan) came on immediately. WOOHOO I thought my previous troubles were a fluke.
NOPE. A few minutes down the road, and she overheats again. I park, pop the hood, and the drivers side fan (e-fan) is no longer running. I go home, turn the jeep off, pop the hood, turn the jeep on again, and then try the a/c. No luck on the the drivers side fan coming on.

I let it sit for a few hours. I try again. Pop hood. Turn on jeep. Turn on A/C. and the fan immediately turns on . I notice the fan may seem a little slow, possibly a little wobbling (not erratic). I watch it for a few minutes and I notice the fan slow down a bit, then goes slightly faster. But ultimately a few minutes later the fan turns off entirely. Thats where I left it, and began my search on the forum, but yet to see anything on this particular issue.

My jeep is a 1998. 4.0 4x4 Classic (I noticed years matter how the cooling system works)

So the overall question is what's yawls thoughts / opinions?

All the posts I've read are simply about the fan(s) not working period ... or not shutting off when the jeep is off.
This situations seems different in that it starts off working (possibly slow though), and then turns off.
Also, when the a/c is on its blowing cold and I do hear the clutch engaging intermittently, and the fan on the passenger side is spinning.

Thanks as always for the the future / potential help and comments.

I"m also now wondering if this is just a side issue, and there is a more serious issue going on other than the e-fan not working properly. Something to do with the a/c maybe?
 
Overheating at idle, in stop and go traffic, or on the 4x4 trails is typically a weak mechanical clutch fan.

The stock Cherokee cooling system, even when in perfect condition, is not that far from being overwhelmed. The engine compartment is very tight, and the AW-4 transmission tends to run hotter than most others. Both routine maintenance and preventative maintenance of the cooling system are critical.

If you suspect any of the cooling system parts are worn out, weak, or failing they should be serviced or replaced. You should also be inspecting for mud/grass/bug blockage of the A/C condenser and internal/external blockage of the radiator. I would replace the fan clutch, the e-fan, the e-fan relay, and the coolant temp sensor at the very minimum. The Cherokee fan shroud is required.
 
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would all those go bad at once, to cause this???
Or is that more of “throw some parts at it and see if it works”

Obviously somethings wrong, but I’m hoping there might be a way to specifically find the issue, rather than toss money and parts and potentially still be wrong. Definitely appreciate the reply!
 
Overheating at idle, in stop and go traffic, or on the 4x4 trails is typically a weak mechanical clutch fan. Either the e-fan works right every time, always, or it doesn't.


Is all of your cooling system maintenance current ? Based upon your diagnostics and symptom descriptions, a new fan clutch and an e-fan is hardly "throwing some parts at it".

Things wear out. Failure to replace worn or failing cooling system parts can lead to catastrophic failure of the engine. Now, instead of a few bucks for routine maintenance parts, you are looking at a hefty repair bill.

YMMV.
 
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If you think the electric fan, or the lack of it is causing overheating, jumper the fan motor so it runs all the time and then see if it still overheats.
Adding a dash switch to allow the electric fan to run all the time is a common mod.
If the fan stops running, you have some troubleshooting to do. When the fan should be on and isn't spinning, is it locked up or not getting power, two possible problems to check.

Tim's suggestion that the fan clutch is weak is a good one, the fan clutches seem to lose their strength out after just of couple years, I have had several go bad on trips and carry a spare for summertime outings.
For mostly off-road work in the summer, a stock ZJ clutch fan is more powerful and cools better, with the downside of more noise and slightly less mileage.
 
Had all of about 2 seconds to look at it today.

started the Jeep. Saw e fan run. Then it stopped. I tapped the blade and it started slowly spinning again.

figured that alone was enough to show the fans bad... so ordered a new one.

Again, would be great if that’s the only issue

And thanks for the above comments!
 
Finally got around to replacing the e-fan tonight after work, in the rain. Got the new one installed and the fan seemed to run MUCH better than my old one.
I let it idle with A/C on full blast for about 10 mins.
Drove it for about 30 minutes.(a/c on high)
Once back home I let it idle again for about 10 mins. (a/c on high)

I'm not ready to 100 percent that my issue is solved, and that's only because the temperature outside was in the low 50's, compared to 80's when I was having the issue.*
I am pretty hopeful however since I let it run for a good bit, and she never even touched 210. I drove around for those 30 mins freezing my tail off, as I blasted the A/C, and the outside temp being 50's (also being soaked from the rain).*
When I had the issue(s) the temp would peg out in short time after turning on the a/c. So again, pretty hopeful!*
 
Yeah sounds like the fan was failing, you might test the voltage going to the fan and see if the power to the fan is dropping off or if it's staying steady while the fan stops. If the voltage is dropping it probably a sensor or a relay, if the voltage is holding steady but the fan is stopping it must be the fan
 
Similar thing happened to me, my problem was the electric fan plug connector melted causing intermediate connection. So check the wiring - it was obvious once I unplugged the connector. You would have saw it when you changed the fan out but something to think about. Also check the wiring length to make sure its not exposed and grounding on something.

If you still have problems I would change the mechanical fan too like other people said. It is a wear item and does need to be replaced because of the viscous fluid inside
 
Well, all seems well. I’ve driven it all weekend, in much warmer temps with a/c going, and she did just fine.
Today I even drove it two hours away to do some scouting for future camp sights, and trail riding a bit, then back home another two hours. Zero issue.
thanks everyone who commented.

*** to those who my stumble across this thread in the future when doing *keyword searches* for “only overheating with a/c running”
.....check your e-fan (for ‘98 models at least).
At only $40-50, and all of about 5 minutes of labor, my issue was solved.

​​​​​​​thanks again to those who commented above
 
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