Overheating Issues

uvalax236 · **Posted:** Tue May 30, 2006 6:08 pm

So I was driving down the freeway this afternoon and noticed that the KJ seemed a little "weird driving". I look down and my Jeep is regestering that the engine is about 3/4 to H on the temp! Now the outside temperature here in Richmond today was 97*. Yesterday it was 95*. I have a Flowmaster 40 series, Custom Cold Air Intake, and an ARB with a Warn Winch on the front (all has to due with weight and engine mods). I have 41,000 miles on the OD on my 02 sport. Should I look into flushing the whole coolant system? Could my water pump be going bad? Anyone know what I should do to stop this? It has happened before on trail rides but that was fixed after a few gallons of water went on the radiator. Please help!

Jeepjeepster · **Posted:** Tue May 30, 2006 6:26 pm

There is only a couple of things it could be. Going down the highway it could only be the radiator, water pump, or thermostat. You also said it did it off-roading one day, that could of been a bad fan and all of the above.

Jeepin Al · **Posted:** Tue May 30, 2006 6:27 pm

Hey Richard,

Try again to clean the mud out of the radiator. Garden hose on the inside to push outwards towards the grill. You will be amazed on what comes out! Next check to see if the electric fan is coming on. After that if all else fails flush the system, remove the t-stat and test. I used a small block chevy (78-82) 180 degree and it works.

Check to make sure the winch isn't blocking the air flow. I would bet its mud in the radiator fins, but.... check the above.

Al

FreeJeep · **Posted:** Tue May 30, 2006 6:59 pm

You might want to test with you AC off. Looks like me AC compressor clutch is screwed up(sounds like it has marbles in it:-/). Every time I turn the AC on, the temp jumps WAY up. Turn the AC off and it drops back to normal. Going to work on it this Thursday, will let you know what I find out.

DonC

Jeepjeepster · **Posted:** Tue May 30, 2006 7:03 pm

Jeepin Al wrote:

Hey Richard,

Try again to clean the mud out of the radiator. Garden hose on the inside to push outwards towards the grill. You will be amazed on what comes out! Next check to see if the electric fan is coming on. After that if all else fails flush the system, remove the t-stat and test. I used a small block chevy (78-82) 180 degree and it works.

Check to make sure the winch isn't blocking the air flow. I would bet its mud in the radiator fins, but.... check the above.

Al

Gosh Im stupid, cant believe I forgot mud. What really makes me stupid is our work truck has been overheating for the past week(since it go hot around here) and mud in the radiator is the problem. They have yet to fix the problem and I cant see this engine lasting much longer since it gets into the red almost everyday, and we drive over 150miles a day.

liberated4life · **Posted:** Tue May 30, 2006 7:50 pm

If cleaning it doesn't work then try squeezing a coolent hose and have someone rev the engine. If the coolent hose presses outward then the pump is fine. Check the cooling capabilities of the coolent itself with a hydrometer to see if it has adiquate protection properties. If the fan is kicking on and the coolent is good and the pump is operating then the thermo is probably to blame, assuming you made sure that airflow is unrestricted. Good luck and let me know how it turns out!

jason thompson · **Posted:** Tue May 30, 2006 8:36 pm

i would bet that it is some thing with the radiator
my little brothers YJ had a very simular problem that when he drove at highway speeds for more than 15-20 mins it would over heat how ever ride trails all day with out a blink at over heating
we replaced every thing but the radiator and it still did it then we replaced the radiator and BAM he could do 80 with no prob
other than a little wobble it sits on 35's with 4 1/2" lift

KJ04 · **Posted:** Tue May 30, 2006 9:28 pm

In the event that the fan is not coming on, pull the fan motor apart and clean the mud out of it also. Yeah, mud cakes up on the brushes and doesn't make contact on the armature. Pack the rear copper contacts with Die-electric greese too.

uvalax236 · **Posted:** Tue May 30, 2006 10:33 pm

Alright well I will be tearing into the KJ this saterday (while at an install party) so I will let yall know how things go. I am going to spray the radiator again but the way Al said. Thanks for the quick responses and I will let yall know how things go!

Noscapegoat · **Joined:** Thu Jan 05, 2006 11:45 am **Posts:** 104

Yeah my jeep overheated today after some heavy mud I think I just need to clean the radiator out real good.

Also I notice the Fan doesnt always come on does anyone know if thats controlled so it only comes on when it needs it?

lilmatty · **Posted:** Wed Jun 07, 2006 11:59 pm

My guage recently showed overheating but the engine after popping the hood was cool. Turned out to be the sensor.

But this after demudding the radiator, replacing the clutch fan but before the misery of replacing the thermo.

Noscapegoat · **Joined:** Thu Jan 05, 2006 11:45 am **Posts:** 104

Not to be a n00b but I can't get the radiator fan unpluged! please help!

EDIT: Nevermind my brain wasn't functioning properly. I have figured it out.

JFortier777 · **Posted:** Sun Jun 11, 2006 12:01 pm

Hey I had a similar problem and will be heading to the dealer on monday for it, heres a link to my thread with a few pics of the problem.

http://www.jeepkj.com/forums/viewtopic.php?p=33934#33934

A good way to test the fan is to turn your AC on full and pop the hood. AC is a direct switch to the fan so if it doesnt turn on its a good indicator that the fan is bad.

Noscapegoat · **Joined:** Thu Jan 05, 2006 11:45 am **Posts:** 104

KJ04 was right I pulled my radiator fan out took the motor out washed the mud out with water. After letting it dry over night just sprayed some WD-40 on it to water proof it put it back in and started working right away!

I thought I was gonna need a new fan!

KJ04 you outta make a tech article about it with pictures because this will probley help alot of people out. Sure helped me.

AdamIsAdam · **Posted:** Tue Jul 18, 2006 10:45 pm

I had the original colant (2003 with 54k) and yesterday and today I noticed the temp gauge rising during the 98* day. It went to about 3/4 mark, and it normally DOES NOT MOVE from the midway mark. I knew I was overdue, so I flushed the system completely, and while I had the stuff apart, I replaced both hoses and the thermostat.

The manual says you need to remove the thermostat to flush the block/system anyway, so for $20, I put a new one in. The hoses were about $10 each.

As for the radiator fan fix. there was a write up on this a while back. I'm not sure if it still exists, but I read it on the old board and remembered enough to help out Steve on a Jamboree in May. His fan got caked after this pass:

So we pulled the fan shroud and then fan during lunch. It was pretty straight forward. Two screws to get the shroud out. Then hand tools to take the fan motor apart. Once installed, I took a toothbrush to his radiator to remove the MAJOR buildup, and he was good as gold.

(NOTE: he doesn't have the mechanical fan.)

By the way, the fan will only come on with the engine RUNNING, not just the key in hte ON position and AC on. It's too smart for us dopes and our test lights.

Here's the pic of us taking it apart. I'm the one behind the lense :wink:

RespectMyLibertay · **Posted:** Wed Jul 19, 2006 1:59 am

I had my engine fan recently go out on me, causing me to overheat the engine. I first thought it was the coolant system but looked to find the fan never turning on when idling. I pulled it out to find the motor not responding to 12 volts, so I took that apart and cleaned out some small mud chunks between the conductors. That fixed it, but I hope it doesn't act up again.

Overheating Issues

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