HELP KJ Can't stay Cool

04jeepkj · **Posted:** Sun Jun 22, 2008 10:10 am

Ok doing some pretty good wheeling yesterday and about halfway through the temp gauge spiked and engine started to smoke, coolent boiling and a small leak in the radiatior. . . So let her cool down put some water in and made a temp fix on the radiator. got back on the trail and not 2 mins later temp spiked again and coolent boiling from the tank. Got her off the trail let her cool down for 3 hours, no leak, started up fine, after 2 mins of driving temp spiked yet again.
And i have no clue what is causing the KJ to do this. . . There are however a few thing i noticed, the cooling fan doesn't seem to be coming on at all, Turning on the heat full blast brought the temperature down a little. And Jeep did a pretty good job on hiding the thermostat. . .

Anyone else have any issues like this? Any ideas?

The KJ is an 04 3.7L V6.

Jeep4me99 · **Posted:** Sun Jun 22, 2008 10:31 am

did you change the coolant lately? Refill with the right kind?

JJsTJ · **Posted:** Sun Jun 22, 2008 11:18 am

Did you play in any mud? Could be the radiator is plugged w/ mud and air can't get through. May have damaged the electric fan too in the process??

04jeepkj · **Posted:** Sun Jun 22, 2008 11:23 am

I stomped in alot of mud puddles. . . The fan now comes and goes. . . let her sit in idle and temp is still climbing. going to try and clean some more mud out the radiator. . .

Fulltimer · **Posted:** Sun Jun 22, 2008 12:00 pm

If you didn't, take it to a car wash and use the power washer to give the radiator a good cleaning. After I hit some mud on a trail it did the same thing. I made it to the closest car wash and everything went okay after that. But getting there was VERY hot! :lol:

Terry

04jeepkj · **Posted:** Sun Jun 22, 2008 12:12 pm

if the radiator is clogged up why is the fan still not kicking on. . . i think my problem is more than just mud in the radiator. I think the high fan relay might be dead. . .

KJ04 · **Posted:** Sun Jun 22, 2008 3:36 pm

04jeepkj wrote:

if the radiator is clogged up why is the fan still not kicking on. . . i think my problem is more than just mud in the radiator. I think the high fan relay might be dead. . .

Pull your fan shroud out, and take the fan motor apart and clean it. Comutator brushes are most likely caked from going through deep muddy water and not making electrical contact. Had it happen to mine a few times and now I stay out of the deep muck.

Very easy to disasemble and clean, took me about 45 mins.

kskj · **Posted:** Sun Jun 22, 2008 5:03 pm

The same thing happend to me on the trail,drove through some deep muddy water then it started over heating.The fan was not working so i took it out and cleaned it up .It was only a light film of mud but it kept it from turning. havent had a problem since.

jason thompson · **Posted:** Sun Jun 22, 2008 7:29 pm

You know what the problem is
no fan = no air flow
no air flow = over heat

I would #1 stay out of the mud
#2 replace fan with an after market fan from a company like flex a lite

now if you feel you just can not avoid the mud ,problem I have, then a mechanical fan would be a better choice
but I would figure out a way to have both as my mechanical only system can not keep the 4.0 in the TJ cool from mid May until mid September out on the trail ,it does fine on the road but slow trail riding kicks it in the arse
Now it would do alright if I ran with no AC but I am to old for that crap

tjkj2002 · **Posted:** Sun Jun 22, 2008 7:35 pm

Might also want to check the fan relay that is mounted about 10" below the battery in the engine bay,if it get's to hot it can stop working and the newer version come with a oversized heatsink to keep them cool.

And like stated before,clean the junk out of the radaitor and condensor,clean the fan brushes,and most important point is STAY AWAY FROM MUD OR MUDDY WATER!!!!!!!!!!!!!!!!!!!!!!!!!!!

NomadKJ · **Posted:** Mon Jun 23, 2008 4:40 am

Mopar part# 82208909 Heavy-Duty Cooling fan kit for 3.7L V-6 engine (The kit has both the electric & mechanical fan).

jason thompson wrote:

You know what the problem is
no fan = no air flow
no air flow = over heat

I would #1 stay out of the mud
#2 replace fan with an after market fan from a company like flex a lite

now if you feel you just can not avoid the mud ,problem I have, then a mechanical fan would be a better choice
but I would figure out a way to have both as my mechanical only system can not keep the 4.0 in the TJ cool from mid May until mid September out on the trail ,it does fine on the road but slow trail riding kicks it in the arse
Now it would do alright if I ran with no AC but I am to old for that crap

FreeJeep · **Posted:** Mon Jun 23, 2008 6:33 am

Might also want to check your waterpump. Mine died at about 50k miles. Won't affect the fan, but may be part of the problem.

DonC

04jeepkj · **Posted:** Mon Jun 23, 2008 9:17 am

NomadKJ wrote:

Mopar part# 82208909 Heavy-Duty Cooling fan kit for 3.7L V-6 engine (The kit has both the electric & mechanical fan).

About how much is it and how much of a pain in the stupid is it to install?

oldhockeyvb · **Posted:** Mon Jun 23, 2008 3:01 pm

Don't forget the radiator cap. A bad cap won't hold pressure and will spike the temperature and steam the water

jason thompson · **Posted:** Mon Jun 23, 2008 6:46 pm

Guys I have seen a bunch of posts all pointing to things that "could" cause his problem
but if you read the first post he said "the fan is not coming on at all" and he also said that the problem happened on a trail
which means about as bad as it gets when it comes to generating heat it also means that he was going very slow
which means that there was even less air flow

:?:

tjkj2002 · **Posted:** Mon Jun 23, 2008 6:57 pm

jason thompson wrote:

Guys I have seen a bunch of posts all pointing to things that "could" cause his problem
but if you read the first post he said "the fan is not coming on at all" and he also said that the problem happened on a trail
which means about as bad as it gets when it comes to generating heat it also means that he was going very slow
which means that there was even less air flow

:?:

That's why I responded with this...........

Quote:

Might also want to check the fan relay that is mounted about 10" below the battery in the engine bay,if it get's to hot it can stop working and the newer version come with a oversized heatsink to keep them cool.

NomadKJ · **Posted:** Mon Jun 23, 2008 7:42 pm

The cost is $233.00 from; http://www.chryslerpartsdirect.com/.

It depends on your mechanical abilities. Remove existing electric fan and shroud, install new fan, shroud, and mechanical fan.

04jeepkj wrote:

NomadKJ wrote:

Mopar part# 82208909 Heavy-Duty Cooling fan kit for 3.7L V-6 engine (The kit has both the electric & mechanical fan).

About how much is it and how much of a pain in the stupid is it to install?

NomadKJ · **Posted:** Mon Jun 23, 2008 8:11 pm

INSTALLATION:
NOTE: For 3.7L Heavy Duty/Max Cool/Trailer Tow cooling package, the viscous fan cannot be installed separate from the shroud. Both fan and
shroud must be installed together.
(1) Gently lay viscous fan into shroud.
(2) Install fan shroud assembly into the vehicle. Tighten fan shroud to radiator bolts to (5.5 N•m (50 in. lbs.).
(3) Using special tool 6958 spanner wrench and 8346 adapters, install the viscous fan on the water pump.
(4) Connect fan motor wire connector to harness connector, and attach connector to shroud.
(5) Connect battery negative cable.
(6) Start engine and check fan operation.

OPERATION:
A thermostatic bimetallic spring coil is located on the front face of the viscous fan drive unit. This spring coil reacts to the temperature of the radiator
discharge air. It engages the viscous fan drive for higher fan speed if the air temperature from the radiator rises above a certain point. Until additional
engine cooling is necessary, the fan will remain at a reduced rpm regardless of engine speed. Normally less than 800 rpm.
Only when sufficient heat is present, will the viscous fan drive engage. This is when the air flowing through the radiator core causes a reaction to the
bimetallic coil. It then increases fan speed to provide the necessary additional engine cooling.
Once the engine has cooled, the radiator discharge temperature will drop. The bimetallic coil again reacts and the fan speed is reduced to the previous
disengaged speed.

04jeepkj · **Posted:** Wed Jun 25, 2008 4:23 pm

For now i just went with the stock electric fan for now, cause i have to check in and ship out to iraq next week. . .

Well i got the kj back to a safe place, and started taking things apart. . . Took the KJ to the dealer to see what issues and if the problem was something more than i could trouble shoot and fix. . . turns out it was just the fan. So i went and got the KJ before they could start working on replacing the fan cause they wanted $465.00 to fix it HA HA HA NOT!!! Got a fan on its way for $140, and paid the dealer $35 for them telling me thats what was wrong with my KJ.

So i took the old fan out, cleaned it and its still dead so i am waiting for the new one to get here in the morning, meanwhile i will be cleaning out all the mud and stuff from the radiator and other now easier places to get too.

HELP KJ Can't stay Cool

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