Trouble with my KJ.

  • Hi Guest, you may choose a LIGHT or DARK theme that works best for you with the "Style Chooser" button at the bottom left on this page!
  • HTML tutorial

Robert OB 33/48

Mid Europe Region Director
Founder 500
Member
Supporter

Pathfinder II

4,387
Gaanderen
First Name
Robert
Last Name
Keim
Member #

0033

Hello folks,

Yesterday a short weekend trip came to an end right in the beginning.
After fillinbg up gas and hitting the highway, my coolant tempature slowly but steadily increased.
Even with my chicken fan ( I can start this one manually ) I couldnt provide enough cool air to drop the tempature.
So, we stopped at a parking spot and when the car was running idle the tempature dropped untill it was "good".
However as the coolant had boiled, I lost a bit of fluid, so we decided that the trip was over and that now with some extra care we could be home in "one" piece.

The history;
Last year, same month, a weekend trip was as short as this one due the same sort of problem.
Then I thought the head gaskets were the problem. I have a new set of them now in storage.
It turned out the fans didnt work. The fan that is started when the climat control is on. That is an electrical fan and a mechanical one which should start when it reaches around 95 degrees celcius.
I changed both and all was good.

So, this year the "same" problems again.

I thought that I fixed again the problem last week, as the connector to the electrical fan was bad.
Not burned but more damaged due age. The KJ is from 2003 and has 250.000 km on the clock.
I replaced the connector with simple wires and universal connectors and the fan worked when needed properly.

Now to the present day.
Going on the internet/You Tube and tried to figure out what is the problem.
What is said the most is the following;

1. Thermostat.
2. Water pump
3. blocked waterways. so flushing the cooling system.
4. head gaskets.

As I checked, and rechecked and triple checked my coolant and oil, there is no sign that the head gaskets are gone.
I will check the exhaust for white or blue smoke today.

So what is my plan?
Ordering;
A new Thermostat.
An infrared thermometer. So I can check the tempature on different locations.

Today;
Check both fans.
Check the exhaust for bad gasses.

Monday if the thermometer is in checking the tempature.

So, next monday I hope I have more information.

Greetings from Robert
 

grubworm

Rank V
Member

Member III

2,358
Thibodaux, LA, USA
First Name
grub
Last Name
worm
Member #

17464

Ham Callsign
WRMA515
Service Branch
USN-Submarines
we had a similar problem a while back with my wife's jeep sahara and it was the thermostat. luckily a cheap and easy fix that took about 15 minutes and a few bucks to fix. hope you have the same good luck....
do you have a check engine light? we did and i have a cheap code reader that told me thermostat, so i basically had zero troubleshooting to do
 
Last edited:

Robert OB 33/48

Mid Europe Region Director
Founder 500
Member
Supporter

Pathfinder II

4,387
Gaanderen
First Name
Robert
Last Name
Keim
Member #

0033

Tested the car this morning.
Tempature was up the most till 101 celcius.
Noticed that the motor fan didnt work. So, I will take it out and fixate it again.
Will order one and that is an easy fix as well.

Together with the thermostat it should be better.
I hope.
Noticed that the fan for the climat control did work.
And I guess I have a leak in my climat control circuit. That I will have checked later on this week.
 

Robert OB 33/48

Mid Europe Region Director
Founder 500
Member
Supporter

Pathfinder II

4,387
Gaanderen
First Name
Robert
Last Name
Keim
Member #

0033

20210619_172841.jpg

Again, the visco coupling of the fan didnt work at least not below 101 celsius. Which should start working at 95 C.
So, took it out and drilled it through, bolt through it and now it should work all the time.
Tomorrow a testrun with it.
Hopefully monday or tuesday the new thermostat is coming in.
I already ordered a new Visco.
I hope it arrives soon. USA and EU not the fastest, cheapest and easiest way to buy.
 

MazeVX

Rank V
Member

Member III

2,741
Gießen Germany
First Name
Mathias
Last Name
Kreicker
Member #

8002

View attachment 201928

Again, the visco coupling of the fan didnt work at least not below 101 celsius. Which should start working at 95 C.
So, took it out and drilled it through, bolt through it and now it should work all the time.
Tomorrow a testrun with it.
Hopefully monday or tuesday the new thermostat is coming in.
I already ordered a new Visco.
I hope it arrives soon. USA and EU not the fastest, cheapest and easiest way to buy.
Did you check the possibility of a upgraded visco fan? They are available for the wrangler, at least I believe that, and this is more or less the same engine as in the first years of the JK wrangler.
 
  • Like
Reactions: grubworm

Robert OB 33/48

Mid Europe Region Director
Founder 500
Member
Supporter

Pathfinder II

4,387
Gaanderen
First Name
Robert
Last Name
Keim
Member #

0033

I was thinking about it. But today I cleaned my engine bay and also the fan for the climat control, and the radiator.
Now that bloody climat control fan doesnt work. Probarly a bit too much water in it.
I will take it out tomorrow and dry clean it and put in some WD40.
I hope it will work again.
But if I have a electrical fan and go through water, it could spoil the day.
 
  • Like
Reactions: MazeVX

Robert OB 33/48

Mid Europe Region Director
Founder 500
Member
Supporter

Pathfinder II

4,387
Gaanderen
First Name
Robert
Last Name
Keim
Member #

0033

Did the testdrive today.
Conclusion its the visco coupling of the Fan.

I ordered a new one.

So, I still will replace the old thermostat and will flush the whole cooling system. Then new coolant in it.
The fixated visco coupling will get a permanent place in the car with the special tool/wrench I have to use to loosen that thing.

I have ordered an infrared thermometer so I can really check the flow of the coolant with heat differences. ( knowing through testing and measurement instead of gambling)
I will order an OBD2 display plus sensor and through that I will be able to have a better read out wath really is going on in the car.
For now my bluetooth OBD2 sensor and smartphone will do the trick.

I hope that coupling will arrive this week. As I need the car next saturday.
Then if all is installed the last testdrive again.
 
  • Like
Reactions: MazeVX and grubworm

Lanlubber

Rank V
Member

Member III

2,827
Mimbres, NM, USA
First Name
Jim
Last Name
covey sr
Member #

16986

Ham Callsign
none - BREAKER BREAKER HAND HELD CB AND WALKIE TALKIE
Hello folks,

Yesterday a short weekend trip came to an end right in the beginning.
After fillinbg up gas and hitting the highway, my coolant tempature slowly but steadily increased.
Even with my chicken fan ( I can start this one manually ) I couldnt provide enough cool air to drop the tempature.
So, we stopped at a parking spot and when the car was running idle the tempature dropped untill it was "good".
However as the coolant had boiled, I lost a bit of fluid, so we decided that the trip was over and that now with some extra care we could be home in "one" piece.

The history;
Last year, same month, a weekend trip was as short as this one due the same sort of problem.
Then I thought the head gaskets were the problem. I have a new set of them now in storage.
It turned out the fans didnt work. The fan that is started when the climat control is on. That is an electrical fan and a mechanical one which should start when it reaches around 95 degrees celcius.
I changed both and all was good.

So, this year the "same" problems again.

I thought that I fixed again the problem last week, as the connector to the electrical fan was bad.
Not burned but more damaged due age. The KJ is from 2003 and has 250.000 km on the clock.
I replaced the connector with simple wires and universal connectors and the fan worked when needed properly.

Now to the present day.
Going on the internet/You Tube and tried to figure out what is the problem.
What is said the most is the following;

1. Thermostat.
2. Water pump
3. blocked waterways. so flushing the cooling system.
4. head gaskets.

As I checked, and rechecked and triple checked my coolant and oil, there is no sign that the head gaskets are gone.
I will check the exhaust for white or blue smoke today.

So what is my plan?
Ordering;
A new Thermostat.
An infrared thermometer. So I can check the tempature on different locations.

Today;
Check both fans.
Check the exhaust for bad gasses.

Monday if the thermometer is in checking the tempature.

So, next monday I hope I have more information.

Greetings from Robert
I'd bet it is your thermostat ! It could be a good thermostat and still overheat because it may be the wrong temperature regulator but not likely if you've had it for awhile and no problems. (Low altitude or high altitude thermostat)
Good luck !
 
  • Like
Reactions: grubworm

Robert OB 33/48

Mid Europe Region Director
Founder 500
Member
Supporter

Pathfinder II

4,387
Gaanderen
First Name
Robert
Last Name
Keim
Member #

0033

Thermostat is ordered and will be replaced.
And while that doing I will flush the whole coolant system out.
Thank you.
 

grubworm

Rank V
Member

Member III

2,358
Thibodaux, LA, USA
First Name
grub
Last Name
worm
Member #

17464

Ham Callsign
WRMA515
Service Branch
USN-Submarines
Did the testdrive today.
Conclusion its the visco coupling of the Fan.

I ordered a new one.

So, I still will replace the old thermostat and will flush the whole cooling system. Then new coolant in it.
The fixated visco coupling will get a permanent place in the car with the special tool/wrench I have to use to loosen that thing.

I have ordered an infrared thermometer so I can really check the flow of the coolant with heat differences. ( knowing through testing and measurement instead of gambling)
I will order an OBD2 display plus sensor and through that I will be able to have a better read out wath really is going on in the car.
For now my bluetooth OBD2 sensor and smartphone will do the trick.

I hope that coupling will arrive this week. As I need the car next saturday.
Then if all is installed the last testdrive again.
good troubleshooting skills!

you can make a few wrong guesses on swapping parts yourself and STILL be way under what a mechanic would charge to do one thing.
 

rho

Rank V
Member

Member III

2,031
SF bae area
First Name
Juliette
Last Name
Penning
Member #

18700

Ham Callsign
AG6YB
I'd look into replacing the fan coupling with a new unit when you can, the power losses coming from having the fan fully engaged all the time are often quite large. Additionally if the fan is overcooling, it can hide other symptoms that might still be occurring in the system.

Oh, i see you got a new one. GOOD!

Something else to look into is if the cooling system has any leaks anywhere or if there is part of the system that isn't holding pressure when the motor gets hot. A fairly common failure mode is for the bearing in the water pump to go out and then for it to start leaking form the pulley shaft/bearing. Just something else to take a look at the next time you're crawling around in there.
 
  • Like
Reactions: Robert OB 33/48

Robert OB 33/48

Mid Europe Region Director
Founder 500
Member
Supporter

Pathfinder II

4,387
Gaanderen
First Name
Robert
Last Name
Keim
Member #

0033

Checked the waterpump as I know that problem to waterpumps in general, no fluids/water/coolant traces there.
And no notable play in that bearing as well.

Thank you for that. Always good to have more info to work with.
 
  • Like
Reactions: MazeVX