Overheating Issue

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ckenney35

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I've got an issue and I'm a little confused. My 03 liberty is overheating but the thing about it is if I'm driving faster than 45 than it does fine as long as its not above 80 outside. I can turn the heater on if I'm driving slower than 45 and it will help keep it in check. It's never overheated past the hash mark past the middle. I've changed the fan relay and the thermostat. It doesn't show any classic signs like white in oil or coolant smell in oil to indicate blown head gasket. The oil is the right level and plenty of coolant in resivoir.

What should I check and start replacing?
 

ckenney35

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I've got an issue and I'm a little confused. My 03 liberty is overheating but the thing about it is if I'm driving faster than 45 than it does fine as long as its not above 80 outside. I can turn the heater on if I'm driving slower than 45 and it will help keep it in check. It's never overheated past the hash mark past the middle. I've changed the fan relay and the thermostat. It doesn't show any classic signs like white in oil or coolant smell in oil to indicate blown head gasket. The oil is the right level and plenty of coolant in resivoir.

What should I check and start replacing?
Maybe I should clarify. The normal temp on the gauge is the hash mark in the middle....when car starts to overheat I have pulled over and shut off before it has ever gotten to the next hash mark up from that. Just saying that to hope that I've not done and damage to engine

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Billwill

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Is the electric fan actually coming ON?

You may have air in the system and need to burp the air out.

Is coolant a mix of clean water and HOAT anti-freeze?

Radiator clean of insects, grass etc.?

System under pressure when warm ie. radiator cap working properly?

Could be thermostat or water pump.
 

ckenney35

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Is the electric fan actually coming ON?

You may have air in the system and need to burp the air out.

Is coolant a mix of clean water and HOAT anti-freeze?

Radiator clean of insects, grass etc.?

System under pressure when warm ie. radiator cap working properly?

Could be thermostat or water pump.
Don't see an electric fan, I see the belt driven fan

How would I burp the system

Weird thing is I do not see a radiator cap. There is a cap on the overflow resivoir but that's it.

I don't see any bugs on radiator but just in case is it safe to wash with hose or power wash at local car wash

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ckenney35

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Is the electric fan actually coming ON?

You may have air in the system and need to burp the air out.

Is coolant a mix of clean water and HOAT anti-freeze?

Radiator clean of insects, grass etc.?

System under pressure when warm ie. radiator cap working properly?

Could be thermostat or water pump.
Also not sure of coolant, it's whatever the tire place put in when I had it flushed last year

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LibertyTC

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How many miles on your 2003 KJ?
No electrical cooling fan Huh? You sure there is not an electrical fan?
Post a photo of what you have in there...
HOAT 0r Zerex-G05 coolant only...flush at the dealer would be recommended!
If it is high mileage throw a new water pump in there, the plastic impeller OEM pumps get eaten by the wrong coolants.
 

JBDive

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ok so is your fluid Green or pink? If it's green, your screwed. The shop put in the wrong stuff and you likely have jelly all through your system.

If it's pink then let's move on:

- As far as I know all Liberty's of that year had both a belt driven fan and electric fan if equiped with the towing package. If the belt driven fan is moving and you can hear the clutch kicking in and out then your good most likely.

- Check for leaks, especially along the corner facing engine, driver's side, of the radiator. There is a plastic bracket there which tends to crack. If you are not maintaining pressure you will have problems.

- Burp the system. You can either use the official way by using the burp plug or park on an incline and let the engine idle will usually do it.

- Fluid at right level?

If the shop mixed your fluids and you are no longer running HOAT then your only safe course of action is to go get a full flushing at a site which uses an under pressure, heated flush with CLR. Even then you will likely continue to have jelly in the system.
 

ckenney35

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ok so is your fluid Green or pink? If it's green, your screwed. The shop put in the wrong stuff and you likely have jelly all through your system.

If it's pink then let's move on:

- As far as I know all Liberty's of that year had both a belt driven fan and electric fan if equiped with the towing package. If the belt driven fan is moving and you can hear the clutch kicking in and out then your good most likely.

- Check for leaks, especially along the corner facing engine, driver's side, of the radiator. There is a plastic bracket there which tends to crack. If you are not maintaining pressure you will have problems.

- Burp the system. You can either use the official way by using the burp plug or park on an incline and let the engine idle will usually do it.

- Fluid at right level?

If the shop mixed your fluids and you are no longer running HOAT then your only safe course of action is to go get a full flushing at a site which uses an under pressure, heated flush with CLR. Even then you will likely continue to have jelly in the system.
I found the electric fan but haven't been able to check if it's kicking on or not yet. The fuse is good though.

Coolant is an orange or almost rust color. I'll be honest it looks like there is rust in the resivoir and on the cap. I do remember the auto shop I take it to told me I could only use dex-cool coolant because it's made by Chrysler.

I also noticed this today while checking hoses for leaks. I can squeeze the top hose on radiator and hear fluid going through hose but whenever I squeeze bottom hose it's almost hard as a rock and I can feel what I assume is rust buildup or something but I don't hear fluid rushing through like on top hose.

If the coolant hurt system how much is the flush gonna cost me and how easy is a water pump change. I'm moderately mechanicly inclined changed many things on my card in the past. As long as I don't have to change engine I should be okay to do myself

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ckenney35

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How many miles on your 2003 KJ?
No electrical cooling fan Huh? You sure there is not an electrical fan?
Post a photo of what you have in there...
HOAT 0r Zerex-G05 coolant only...flush at the dealer would be recommended!
If it is high mileage throw a new water pump in there, the plastic impeller OEM pumps get eaten by the wrong coolants.
It's got 267,000 miles on it but no one knows exact mileage. It was towed behind a camper most of its life before I got it

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melizmc

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Just went through this and changed out my radiator (suspected it was clogged) on Friday after changing my thermostat last week because of the same problem. So far with my test drives, it has not gotten hot on me. The real test will be when I go to work and go up a couple of really long tall hills, where it would get hot on my last week.
 

tommudd

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Any I have to replace a radiator on I also do water pump, thermostat , hoses, radiator cap etc. of course flush the system
 

ckenney35

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Just went through this and changed out my radiator (suspected it was clogged) on Friday after changing my thermostat last week because of the same problem. So far with my test drives, it has not gotten hot on me. The real test will be when I go to work and go up a couple of really long tall hills, where it would get hot on my last week.
I'm hoping I can get it flushed and not have to change out. But I'm prepared to do it if I have to

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J33Pfan

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I'm hoping I can get it flushed and not have to change out. But I'm prepared to do it if I have to

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IMO: Usually you'd replace the thermostat first. Some hoses if they look like they never been changed or worse.
If you never changed the water pump, do it now before you need a new engine.

While your in there you can check to see if there's anything that might clog up your radiator.
 

JBDive

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I'm hoping I can get it flushed and not have to change out. But I'm prepared to do it if I have to

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The "rust" color is probably just dried up HOAT. It is very important to NEVER mix antifreeze versions. HOAT, OAT and of course DEX and anything green. You are unlikely to get rust in the radiator, no steel in there that I know of. The more likely issue is clogs due to jelly.

I had mine outright replaced, didn't cost to much for the work done I didn't think however two years later when I had my engine replaced the mechanic said the whole system was full of crap (jelly) and actually showed me in the engine once it was out how it was almost like a paste internally. We replaced the radiator again then along with all hoses, water pump, thermostat and such.

I'd probably call around and see who can do a real flush where they run CLR through the system, under pressure and heated and how much it cost. Just a drain and flush will prove useless IMHO. After seeing what I saw inside my engine just two years after a radiator replacement and "reported flush" by a "radiator shop" it's pretty clear to me you need it done right which means more than just pulling the plug.
 

Billwill

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I found the electric fan but haven't been able to check if it's kicking on or not yet. The fuse is good though.

Coolant is an orange or almost rust color. I'll be honest it looks like there is rust in the resivoir and on the cap. I do remember the auto shop I take it to told me I could only use dex-cool coolant because it's made by Chrysler.

I also noticed this today while checking hoses for leaks. I can squeeze the top hose on radiator and hear fluid going through hose but whenever I squeeze bottom hose it's almost hard as a rock and I can feel what I assume is rust buildup or something but I don't hear fluid rushing through like on top hose.

If the coolant hurt system how much is the flush gonna cost me and how easy is a water pump change. I'm moderately mechanicly inclined changed many things on my card in the past. As long as I don't have to change engine I should be okay to do myself

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There is normally a high speed fan relay and a low speed fan relay in the relay box under the hood....I will check the 2003 wiring diagrams to check.

Normally pulling out either one of the two relays will cause the fan to run...may be fuse blown, ground missing, wiring fault or the thermo-switch not turning the fan ON but it should turn on when AC is turned ON but let me check the wiring diagrams first. Does the fan turn by hand or has it seized up tight?

The lower radiator hose on my 2002 Export CRD also feels very hard to compress but that is because it has a metal coil wound inside it...probably so that it cannot collapse at any time so I would not worry about that but any rust in the system is not good.
 

Billwill

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OK as I vaguely remembered the 2003 KJs have a different means of turning the radiator fan on compared to the latter models.
There are not radiator fan relays in the relay box under the hood.
This fan of yours only has one speed and it is powered by a single, large robust relay located somewhere in the engine bay...other members here could help with its exact location.

Fuse #2 40 Amps in the box under the hood supplies +12 volts to pin 1 on this relay via a Dark Blue/Pink wire. Ground is supplied to pin 3 on this relay and also to the fan via a Black/Orange wire.

The output of the relay supplies +12 volts to the fan from pin 2 via a Yellow wire. The relay is energized via a Light Green wire on pin 4. This Light Green wire goes through pin 5 on Connector C103 to pin 17 on connector C2 of the PCM. The PCM activates this Light Green wire when the AC Pressure Transducer is good or the Power Steering Switch is good.

So you need to check that Fuse # 2 is OK, Connector C103 is clean and firmly connected, the Black/Orange wire is at ground with reference to +12 volts. So measuring with a voltmeter you need to find +12 volts on the Yellow wire at the fan while the Black/Orange wire on the fan is at ground...all this when the AC is turned ON or supposedly when the engine is hot although this later point I do not see in the wiring diagrams?

The 2003 KJ Service Manual can be downloaded here....has a theory of operations section while the Wiring Diagrams in section 8W gives you the circuitry and also a Locations section which shows you where various connectors are located as well as the ground point G112. Main logic page to refer to is: 8W-30-23

KJ Service Manuals: Index of /manuals/Jeep/KJ
 
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uss2defiant

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I don't know if they made the switch to the two fan relay in the 03/04 changes but if you do have the single fan relay, it is located on the driverside some where below the battery.

The speed is PWM controlled so that is how the speed changes although I didn't see a change in the duty cycle when I was troubleshooting my fan issue.

Here's this thread w/ some info
http://www.jeepkj.com/forum/f196/electric-cooling-fan-help-58534/#post664940
 

Billwill

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I don't know if they made the switch to the two fan relay in the 03/04 changes but if you do have the single fan relay, it is located on the driverside some where below the battery.

The speed is PWM controlled so that is how the speed changes although I didn't see a change in the duty cycle when I was troubleshooting my fan issue.

Here's this thread w/ some info
http://www.jeepkj.com/forum/f196/electric-cooling-fan-help-58534/#post664940

Ok using PWM to control the speed of the fan makes a lot of sense.

Thanks for this information...it means that there will not be a solid +12 volts going to the fan but a pulsed output that can only really be viewed with an oscilloscope!:icon_razz:
 

uss2defiant

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Ok using PWM to control the speed of the fan makes a lot of sense.

Thanks for this information...it means that there will not be a solid +12 volts going to the fan but a pulsed output that can only really be viewed with an oscilloscope!:icon_razz:

Bill, if I remember correctly the Duty cycle was pretty high so a DMM would be able to see it as a DC signal albeit I had a fluke DMM so YMMV with the type of DMM one has.

Again, I may be wrong. This was many many moons ago.
 

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