I went back and re-read post #12, as well as the post 1st post on page 2 by Solomon7.

Honestly, if I had to take a guess, I'd replace the water pump, t-stat, and housing.......after confirming fan functionality with AC off and on. I hear the fan on, but haven't popped the hood to see which one is one and when.

Its pretty hot today here, so will try to heck this after work and then report back.

 

After reading post 22, It sounds like your fan does not kick on at 218 with your AC off. Is this true? And if it does kick on, how fast is it turning? You should be able to hear it blowing.

 

I forgot to come back and report on this.......sorry.

The fan does come on (looking at the front of the Jeep, its the bigger fan on the pass side, right?). It is not spinning fast though......just slow.

 

I am pretty sure it is a one speed fan and should be spinning really fast. i would replace it first. The same thing happened to mine, I could literally stop it with my hand

 

OP/ GS Audio , NO it is NOT the fan on the passenger side. That one is attached to a pulley and is driven by the belt "mechanically" correct? That is the Mechanical Thermal clutch driven fan or Mech. Fan for short. It is ALWAYS running, although it is supposed to lock up and turn more around 180 degrees in the engine bay. If you don't hear a distinct WHIIRRRR from that fan when you goose it and it's hot, it's not locking up properly. It's REAL hard to tell if one's failed an dfor the price just replace it.

If you get the car up to temp, nice and warm, shut off the engine and quickly open the hood and attempt to turn the fan by hand it shouldn't turn hardly at all. This is, however, a VERY objective test. The real way to test is overly complicated involving drilling a hole in the shroud and using a thermometer then running it a 2500 for a while and monitoring temps and sound changes etc. Waste of time and energy over a 40 dollar easy to replace part IMHO.
Mine felt stiff when cold or warm. When I replaced it with the ZJ one when it's hot it won't even turn half a turn.

The fan I believe you are having a problem with engaging appropriately is the small electric fan on the DRIVER's side right in front of the power steering pulleys. This one is referred to as the Auxillary Electric Fan or A/C Fan, (Aux. Fan for short) one and the same as it cools the condenser for A/C and also kicks on when the coolant temp reaches 218 to back up the Mech fan and help drop temps.
There should be 1 black and 1 white wire coming out a coupler pretty much just below and behind you radiator cap. This is the power wires for the fan. There is a temp sender plugged in to your thermostat housing at about 1 o clock. Only thing with wires attached to the thermostat housing. that and 2 hoses lol!

You need to replace that sender and use sealant on it when reinstalling.
Sender is cheap. If you haven't replaced the mechanical fan, you should. they only last about 4 or 5 years at best and I'll bet whoever you got the XJ from didn't, or care even know what is is so it's probably still the original one.
They're cheap and easy. Just 4 bolts (13 or 15mm iirc)on the pulley, place a piece og cardboard/ poster board between the fan and radiator to avoid damage to the rad and your fingers. Undo the shorud screws (2 8mm ones,1 holding overflow tube other on shroud) on top and slide the blades, clutch and shroud out as a whole assembly. It'll be tight but it'll come out. Just be patient to avoid damaging other stuff and yourself.

Once you have it out, remove the fan blades from the clutch. Put the blades on the new one being careful to place them the right direction. There should be "front" printed on one side of the blades.
If you use a stock replacement clutch it's be simple to put back in.
With the HD ZJ one it'll be really tight to get it in, but once in there's 3/4" between it and y radiator. Just fine.
On mine I had to loosen the top radiator mounting plate and rock it back a bit to get the fan in, but mine is thicker than stock. If your radiator is stock size, you shouldn't have to, but figured I'd give you a heads up JIC

total about 65 or 70 bucks for the sender and clutch, and an hour or 2 if it's hot out, and I think your problem will be resolved. If you electric fan is turning visibly slow, you may need a new electric aux/ac fan. I doubt it though, as they run light duty and last quite a while.
Good luck and keep us posted how it turns out!


I haven't noticed much more drag, maybe a bit but it's negligible and probably just in my head. To compare, my old bfg mt km1s were at about 60% wear and I replaced them (warranty) with the new km2s. The new tires' added tread added more lag than the fan, so I say go for it warthog, and every one else.


You go all electric for that. It's a pita and in all reality as I understand it, the mechanical thermal clutch driven fan pulls more air than any electric except the Ford Taurus E fan but it has HUGE amp draw at startup so....
The mechanical fan works better because electric fans pull the same amount no matter what the rpms, so in high rpm low speed applications, an electric fan setup MAY not be enough. The only real advantage to electrical fan setups is you can turn them off for water crossing.
Here's another bummer to converting to an all electric fan setup:
As someone said in another post once said, "If my alternator or other electric component fails, I can drive a couple hours on just the battery with a mechanical fan still cooling. With electric fans not functioning, you've got a couple miles at best before bad stuff starts to happen. DISCLAIMER: The mechanical vs electric debate seems like a mild version of the Dex3 vs ATF4 debate or the ever popular cast iron vs nonstick lol so I try to avoid it. Just stating what I've heard and read regarding the 2 that's all.....My self? I stay mechanical. Just upgrade!

 

OK let me clear this up. I am talking about the electric fan and have been the whole thread

 

Solomon7.....thanks for the write-up.

I assumed the mech fan was belt driven given its location. So when I am driving, it spins faster to perform its cooling duties?

As for the elctric fan, I think warthog has been on point the whole time and I neglected to understand which fan he was refering to. I don't think my e-fan is coming on at 218 as it should......only comes on when the AC is switched on. This should be sensor related, no?

 

Yes it should be the sensor

 

Gonna check that as well tonight.....thanks!

Just want all these little nuisances fixed so I can enjoy my Jeep!!

 

I was the same way. Mine had an overheat problem when i got it. Thats all fixed now and i Love this thing. I could not have bought a better vehicle

 

I located the coolant temp sensor. Once the engine is cold, can I remove this without any coolant leaking out? Will I need to flush the system? Does it create an air pocket in the system? And what can I use to reseal when I put the new sensor in?

Thanks.

 

changed belt driven fan clutch today and cured over heating at idle. checked by turning fan by hand when hot there was no resistance. easy fix

 

This is a "jeep thing".
You might be looking at the wrong end. Are you running your stock cat?
If so, you might be getting a little extra heat from there if it's starting to clog a little...

 

I believe it is the original cat (and possibly O2 sensors).

 

From what I think I correctly checked, I had no resistance on my fan. So I may end up ordering the ZJ one recommended and add it to tyhe to do list when I drop it off for service.