99 jeep xj overheated & boiled over today in the mountains. I suspect maybe the electric fan/ and or the fan clutch as when the engine is off i can spin the Mechanical fan as much as i want.

I hear a weird cazoo type noise randomly from the engine bay and I think it could be the electric fan dying or something. lately every time i turn on the jeep at night after its sat at work 8hrs i hear a weering squeek then i shut the a/c off and its gone ( also makes me think the electric fan).

Heater core is new, Water pump is new, Thermostat is new, Radiator is new all less than 2yrs old.

Also I have another thread to my front axle noise ( Sharp squeal) which i only mention here as i dont know if something could be working the engine so hard that its having trouble cooling- maybe its a long shot but i just got back and all of this is happening at once ARGGGGGh

 

The e fan is nothing but a backup. It shouldn't cause you to overheat

 

ok lets ignore the E Fan. I was driving up to a trail head in 4x4 with A/C on and for the first time ever my jeep overheated and boiled over.

Being that the cooling system parts minus the thermostat sensor are all new, what will cause the xj to overheat. If the fan clutch is gone will that be enough to overheat?

I never had an issue on the way home so something has strained the jeeps cooling and a sensor should be a regular occurrence right?

am i over looking anything,


thanks for the help this is my DD

 

With the A/C on, the condenser ends up heating up the air before it hits the radiator. I definitely think the e-fan is important in preventing overheating, especially in low airflow conditions

As long as you are above 45mph, it should really have no effect unless because its not that strong to begin with. Fan clutch is very important IMO. I can be idling in 120*F ambient air (on the highyway for example), and watch the temp creep up. As soon as I get on the throttle, to around 2K rpm (and the fan is roaring because the clutch is locked up) I can watch the temp come back down.


Both are cheaper than a new head, so I would say replace them if they are several years old. Fan clutch is a wearable item, only lasts so long. With the engine at 215+, the fan should be loud as hell at 2000rpm and up.

A second option is to add an auxiliary trans cooler if you have an automatic, it helps dump some heat out of the engine cooling system, but you kind of have to stack the cooler in front of the radiator anyways so it may be somewhat less effective in that regard

This should be the fan clutch
https://www.amazon.com/Hayden-Automo...kee+fan+clutch

And cheapest e-fan I have come across (new)
http://www.ebay.com/itm/RADIATOR-COOLING-FAN-FOR-JEEP-FITS-CHEROKEE-4-0L-2-5L-L4-4-CYL-V6-6CYL/262288003897?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20160617090737%26meid%3D5856133949d84295bbbcc3a33264aed6%26pid%3D100005%26rk%3D2%26rkt%3D6%26mehot%3Dag%26sd%3D322154636650

 

nuance, the e-fan is only a backup if A/C is off. when A/C is turned on, the e-fan should automatically come on, and stop when you shut the A/C off.

also yes, if your fan clutch is shot and doesn't offer much resistance it will allow temps to rise.

so in conclusion, bad fan clutch + a/c on + e-fan never kicking on = overheating

 

Yep

Check the fuse and relay for the electric fan and replace the clutch

 

i bought a new fan clutch and I can visually see the electric fan is wobbling and screetching off and on. The e fan kicked on once i got back home from the parts store, I did not run A/C at all. she peeked just above 210 barley before it kicked on.

Are there any other test for the fan clutch i can try?

hopefully a new E fan and the clutch will be the solution.

 

Is the fan loud as **** when the jeep is at +215*F?

If so fan clutch is working. If not, the clutch is not locking up. If its loud as **** all the time, the fan clutch probably has failed and is locked-up all the time (which would actually be good in this case)

It should sound greatly diminished when the radiator is cold, and should sound significantly louder when you are at full operating temperature.


Some guys have used a 2x4 to test how much "force" the fan has when the enginebay is cold vs hot

This guy used some rolled up newspaper (probably much safer)
Basically, you should NOT be able to stop the fan that easily when it is at full operating temperature (meaning the clutch should "lock-up" to provide more turning force to the fan itself).

 

sounds like everyone has given very good advice , the only thing I would add is have your pressure cap tested .A bad cap wont keep it properly pressurised which will compromise the proper functioning of the cooling system .

 

Pressure cap huh? I never thought of that one, how do i get it tested?

Also those who have replaced the electric fan which did you buy. OEM Is 300$ holy hell!!!!

 

Radiator cap - if it's in question just replace it (the radiator cap basically "blocks" flow if pressure is too low or high or something). Someone else could probably explain it better, but if it is not functioning properly you will not get proper coolant flow through the radiator.

e-fan?

http://www.ebay.com/itm/Radiator-Coo...hVVfe4&vxp=mtr

I need to buy one of those actually. Went to the junkyard for the 3rd time looking for an XJ e-fan (and dome light) and came up empty


EDIT:
Anyone want to chime in on blade count/orientation? This one is much more "fan-like" as opposed to "turbine like" (not really technical terms, but the pictures should explain)
http://www.ebay.com/itm/Radiator-Coo...9U4wtc&vxp=mtr

I assume one will provide higher airflow and the other (Doorman style) will provide higher static pressure?

 

I dont notice any real difference in how loud the mechanical fan is. the electric fan makes a racket from its draw and the squeals from it dying.

 

so i put the new fan clutch in, and a new e fan both from napa. So far temps dont creep above 210. before i replaced everything temps were just a hair over 210. other than the time it boiled over.

I hope this fixes the issue, Ill have to head to the hills again and see if something gives!

 

Sounds good!

 

I'm a little late to the party but.....
-the mechanical fan, when cold, should have less resistance to turn than when it's hot
-the 97+ e fans are supposedto move more air due to the design of the blades

Hope this can help someone in the future.