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Overheating Issue
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=1&t=62821		 Page 1 of 1
Author:  Lucky [ Sun Sep 25, 2011 3:04 pm ]
Post subject:  Overheating Issue
Just wondering if this is a common problem...

My jeep has got some kind of overheating problem. The first time I noticed it was when I first went wheeling months ago. Jeep just started heating up on the trails, and I pulled over popped the hood and noticed the fan wasn't running. Checked the fuses and didn't see any blown.

After that, I didn't notice any overheating issues for a while. Then again, I never wheeled it as hard. However, here lately the overheating is happening much more frequently. Very minimal wheeling trips cause it to overheat. Usually it happened when I was moving slowly, meaning not enough wind moving through the engine bay to cool it off. Here, the fan would work sporadically. Sometimes it would be on, sometimes not.

Lastly, I noticed one day that running my a/c and stopping at multiple red lights would make my temp gauge start to climb. I did a test today and found out that:
1 - I could get my fan to come on by turning on the a/c whether the engine was hot or cold
2 - For the 10 min or so I had it running, the jeep did fine keeping the engine at normal operating temperature with the hood open and closed
3 - At operating temperature the fan was not running
4 - Turning the a/c on for about 5 minutes or so after reaching operating temperature started causing my jeep to overheat, but the fan was running during that time
5 - Turning the a/c off left the fan still running, but the engine continued to climb in temperature

Has anyone ever had problems with this?

My first impression is that the fan could be going out or isn't strong enough...

edit: Forgot to mention, when I keep my jeep moving and some wind moving through the engine bay no overheating occurs.
Author:  tjkj2002 [ Sun Sep 25, 2011 10:27 pm ]
Post subject:  Re: Overheating Issue
1st place to start is clean the mud not seen between the radiator and AC condensor,not a easy or fun job.Also check coolant level and for leaks(drivers side upper tank).Then depending on the year check the radiator relay('02-'04 KJ's) on the inner fender,below the battery.Could be a dirty fan motor also.
Author:  Cameraflage [ Mon Sep 26, 2011 3:24 pm ]
Post subject:  Re: Overheating Issue
Sometimes ya gotta do repairs in the field...our cooling fan got so caked with mud that I had to pull it along the trail, disassemble it, clean off the rotor and brushes and then put it back together. It worked fine.

Image

And sometimes, ya just gotta poke it with a stick for a while.

Image

But yeah, like tjkj said, check the radiator for mud...that was our major problem. The fan comes out easy, just 2 screws, and once its out of the way, its pretty easy to get a hose down there to blast it out. I dont recommend using a lot of pressure, though, as you can flatten the fins pretty quickly.
Author:  Lucky [ Mon Sep 26, 2011 4:17 pm ]
Post subject:  Re: Overheating Issue
I've attempted to clean the radiator several times, but maybe I didn't get all the mud out. I'll pull the fan and give it another good cleaning here in the next few days. I'll switch up some relays too and see if that's the problem.

May have to end up taking the fan apart as well. We'll just have to see.

Good suggestions, thanks!
Author:  liquidxit2 [ Mon Sep 26, 2011 6:19 pm ]
Post subject:  Re: Overheating Issue
If mud isnt your issue the plastic blade in the water pump does sometimes separate (mine did in my powertech 4.7). But also its a good measure to replace coolant and the thermostat as well.
Author:  tjkj2002 [ Mon Sep 26, 2011 6:27 pm ]
Post subject:  Re: Overheating Issue
Lucky wrote:
I've attempted to clean the radiator several times, but maybe I didn't get all the mud out. I'll pull the fan and give it another good cleaning here in the next few days. I'll switch up some relays too and see if that's the problem.

May have to end up taking the fan apart as well. We'll just have to see.

Good suggestions, thanks!

If you got mud inbetween the radiator and AC condensor the radiator needs to be partially pulled to clean between the 2,pulling the fan alone is not enough.

Good point about the impeller on the waterpump but that tends to let the engine overheat even at idle which the OP stated it did not do.Oh and the electric fan should nopt come on until about 215 degrees and turn back off at about 198 degrees.
Author:  liquidxit2 [ Mon Sep 26, 2011 6:40 pm ]
Post subject:  Re: Overheating Issue
tjkj2002 wrote:
Lucky wrote:
I've attempted to clean the radiator several times, but maybe I didn't get all the mud out. I'll pull the fan and give it another good cleaning here in the next few days. I'll switch up some relays too and see if that's the problem.

May have to end up taking the fan apart as well. We'll just have to see.

Good suggestions, thanks!

If you got mud inbetween the radiator and AC condensor the radiator needs to be partially pulled to clean between the 2,pulling the fan alone is not enough.

Good point about the impeller on the waterpump but that tends to let the engine overheat even at idle which the OP stated it did not do.Oh and the electric fan should nopt come on until about 215 degrees and turn back off at about 198 degrees.


Good point.
Author:  Lucky [ Thu Sep 29, 2011 12:51 pm ]
Post subject:  Re: Overheating Issue
Update:

THOROUGHLY cleaned out the radiator and a/c condenser. Unbolted the condenser and the top support ( top radiator support/header panel support) and was able to pull the condenser completely. Pulled the fan as well and washed out every inch of the radiator and the condenser through the front and back. When I was finished the water was coming out clear at every point I sprayed. So I think I'm good there.

Sprayed the fan down as well. Didn't disassemble it, but sprayed as much of the inside as possible.

Drove it down the road and heated the engine up to operating temp and turned on the a/c. Continued to drive for a few minutes and everything seemed fine. And then came the true test, parking it and letting it run....

Still overheats. It took longer, so I think the cleaning helped but the problem still remains. I also let it sit at idle with the a/c turned OFF. It took a few minutes, but it overheated at idle as well. I think in my orignal testing I didn't let it sit long enough to overheat while just idling.

With the a/c off, the fan never kicked on, even with the temp gauge sitting at the 3/4 mark. (This is still while the jeep is parked)

I'm thinking the fan has to be the problem at this point. Could this be caused by a fuse?? I suppose I could have missed a blown fuse or read the fuse labeling wrong... I'll have to check again and see if that's the problem.
Author:  tjkj2002 [ Thu Sep 29, 2011 12:56 pm ]
Post subject:  Re: Overheating Issue
Lucky wrote:
Update:

THOROUGHLY cleaned out the radiator and a/c condenser. Unbolted the condenser and the top support ( top radiator support/header panel support) and was able to pull the condenser completely. Pulled the fan as well and washed out every inch of the radiator and the condenser through the front and back. When I was finished the water was coming out clear at every point I sprayed. So I think I'm good there.

Sprayed the fan down as well. Didn't disassemble it, but sprayed as much of the inside as possible.

Drove it down the road and heated the engine up to operating temp and turned on the a/c. Continued to drive for a few minutes and everything seemed fine. And then came the true test, parking it and letting it run....

Still overheats. It took longer, so I think the cleaning helped but the problem still remains. I also let it sit at idle with the a/c turned OFF. It took a few minutes, but it overheated at idle as well. I think in my orignal testing I didn't let it sit long enough to overheat while just idling.

With the a/c off, the fan never kicked on, even with the temp gauge sitting at the 3/4 mark. (This is still while the jeep is parked)

I'm thinking the fan has to be the problem at this point. Could this be caused by a fuse?? I suppose I could have missed a blown fuse or read the fuse labeling wrong... I'll have to check again and see if that's the problem.

What year is your KJ?

If it's a '02-'04 you have a fan relay that is on the drivers side fender about 10" below the battery.They are kinda know to melt and the dealership has a updated part with a bigger heatsink which is cheaper then the stock style aftermarket versions.'05+ and the relay is in the underhood fuse box.I would unplug the fan and jump it straight to the battery and see if it actually turns on 1st,then go after the relay.
Author:  Lucky [ Thu Sep 29, 2011 6:18 pm ]
Post subject:  Re: Overheating Issue
Sorry, I have an 07.

Checked the fuses and the one labeled for the radiator fan is definitely not blown. All the relays are good. I don't know what the "ASD" slot is, but if there isn't a relay there the jeep won't start. I put each relay in that slot and they all allowed the jeep to start.

I think my problem must be the fan. Today, the fan wouldn't come on at all with the a/c on as it has in the past.

Well to see if the fan was stuck, I took a screwdriver and spun the blades on the fan while running a/c.... It started to spin and slowly stopped. Not fast, but you could tell it was trying. I then got the jeep hot, at least hot enough so the fan SHOULD be running under normal operation and used the screwdriver to spin the blades again. Yet again, the fan was very weak, but tried to continue spinning until it stopped.

Which leads me to believe my fan is either dying, or it isn't getting enough power.

Any comments or other suggestions on why the fan wouldn't be working or why it is so weak?
Author:  Lucky [ Tue Oct 04, 2011 12:45 pm ]
Post subject:  Re: Overheating Issue
Wired the fan straight to the battery. Didn't even budge.

Fan is DONE. Suppose it's time for a new one.

Currently looking for a replacement...
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