'04 Liberty overheating only when climbing

[mduclow]

Hi all,

New to the forum,so be kind! My wife and I have an '04 Liberty Limited that we just put a new aftermarket motor in (about 6000 miles ago) with 197,000 miles on it. It has the external trans cooler in it.

Everything is fine with it driving in just about any situation except climbing the mountains here in Colorado. Then it starts running hot, and will overheat if you let it.

I have purged air, it got a new thermostat and water pump with the new motor, the fan runs as it should. It's always just on the short side of half on the temp gauge, until it starts climbing.

I like to go up Rampart Range rd. from Garden of the Gods so it starts the climb at about 6700' and the climb goes to about 9000' or more, during that time speeds will be 10-15 mph and as high as 25 mph, so it's not fast, but not creeping slow either. About 10-15 mins. in the temp will have hit the 5/8's line and be creeping up. If I stop and let it run with the hood open it will cool down in about 5 mins. to the 1/2 line and I will continue, as I keep climbing, so do the temps and I'll have to pull over another 5 mins. or so after starting back up.

My first question is whether or not this is common for this situation, or do I have a cooling issue. If I don't stop to let it cool down the temp gauge won't stop rising, so it is necessary to let it cool down and continue.

Any thoughts or advice is welcome as I am new to Jeeps and don't know all their common issues etc...

Marc

 

[LibertyTC]

Did you install a new Mopar thermostat? Are you using Hoat coolant or Zerex G-05?

 

[tommudd]

Several things ,
as mentioned above,
brand of thermostat
What coolant
what gear are you running in
are you lifted or running larger tires ?
Not a common problem at all
Also is there good circulation in the radiator
Hoses, are they new or old and spongy and closing when hot

 

[Doing10to20]

Damn that's a tough one...so I know people will wanna argue with me but in my experience I've had good results using distilled water to cool my rig..I live in Arizona ,have the big tires ,no regear and go from the valley to the mountains alot and both highway and crawling situations going up in elevation distilled water has given me the best results. Also just a heads up jeeps always run hot unfortunalty

 

[mduclow]

Ok, so it's an automatic and I will run it in drive unless I need to keep it manually in 2nd (which isn't often), it isn't hunting between gears or shifting excessively. I always have the overdrive turned off. Also, it is in 2wd, not 4wd. I don't need the 4wd to run up Rampart, it's a smooth dirt road (a little rough in areas, but don't need the 4wd).

It is not lifted and running 235/70/16 tires. Hoses are also new with the motor, they are not leaking. System holds pressure fine.

The vehicle is fine in all other situations. I can run it up to Turkey Tracks which gets me over 8500' from a baseline of 6400' and it is fine, never moving above the 1/2 way point. It is a daily driver to work and back, 15 miles each way climbing 450', never an issue. It's only ever running hot when it is in a constant (more than 5+ mins.) climb at low to moderately low speeds. The fan is coming on, and the system is definitely holding pressure, everything is as it should be in all but the constant climb at low speeds, then it runs hot.

Now, as to the thermostat and coolant question, I don't know, it was done by the shop when the motor was put in. But I can say this, the thermostat opens and closes as it should be under every other condition, and the temp never goes above a tick below 1/2 otherwise.

I have no idea if the radiator was ever replaced, it does have 197,000 miles on the vehicle, so I'm sure it is worth checking for low flow or something like that.

It's only failing to keep itself cool under constant strain of the climb, but why?

Marc

 

[Billwill]

As stated the correct amount of Red Hoat or Zenex G-05 anti-freeze is needed in the cooling system. All the KJ Service Manuals mention this when referring to overheating issues.

I do not have manuals for the 2004 KJ. Some KJ models have two relays for the electric cooling fan...a High Speed Fan Relay and a Low Speed Fan Relay.

Check in the Power Distribution Module (PDC) which is the fuse/relay box under the hood if you have both relays or only one relay....there can be issues if the High Speed Relay...if fitted... is not energising.

 

[JeepJeepster]

I would suspect the radiator, more so if the history of the Jeep isnt known. Me personally, Ive always kept up on the maintenance and Ive never had a radiator fail by clogging up internally. If you are certain the rest of the system is operating as intended, that only leaves the radiator.

Does your liberty only have the electric fan? Is it running on high speed and not just low speed?

 

[mduclow]

Thank you all for the help and advice so far, it is appreciated.

I checked the fuse box under the hood, it has a low speed and high speed relay, as well as a 40 amp fuse. The fuse looks good, and the fan does run so I assume for now it is fine (the fuse). I do know the fan comes on but I am not aware of ever hearing it at different speeds, so maybe the high speed relay is bad.

I plan to remove the LOW speed relay tomorrow and run the Jeep. If it climbs over the half way point and the fan does not come on, then since I know the fan does come on with the low speed relay in I think I can assume the high speed relay is bad, or the fan motor won't run on a higher speed.

Additionally, after all the talking about this I think I can mostly assume that the cooling system seems to be lacking airflow in the low speed climbing. I say this because it will climb similar distances on the highway and never get more than the strong side of the 1/2 line. Driving out here is almost always above 40 mph, so I think that is adequate airflow for even some climbing with this Jeep, and therefore it is not struggling to stay cool.

So, I'm hopeful I will find out the high speed relay is bad and that fixes my problem. But, as the wise will say, "We'll see!"

And, as JeepJeepster said, it is likely not an optimal radiator in there and may need checking out/replacing in any event.

I am also thinking it might be wise to replace the fan with a higher airflow one given my altitude and grade of some of the mountain climbs out here. It is probably old and wouldn't mind a replacing anyway I bet.

Marc

 

[Billwill]

While your Jeep is hot and the fan is running...pull out the High Speed Relay and see if the speed of the fan changes.

Then with the Relay removed jumper Female pin 30 and 87 together to simulate a High Speed Relay energizing...see if fan speeds up.

You can experiment with swapping the two Relays over and jumping each empty slots 30 and 87 pins together.

Without a 2004 KJ Wiring Diagram I cannot diagnose where the problem may be...check all the fuses are OK.

You could try connecting the two relay coils in parallel so both will always run or connect a seperate switch to manually turn a Relay ON!

I will have a look at the 2005 Wiring diagrams to see how they do things!

I believe you could fix a manual fan in addition to the electrical fan..part of the Tow Package....but that is going a bit overboard...best to fix the problem which could be a clogged radiator or bad water/Hoat mix.

 

[Billwill]

OK according to the 2005 KJ Service Manual:

Engines with AC: In addition to using coolant temperature the cooling fan will also be engaged when the AC is activated. The Relay is also activated when AC is selected and coolant temp is above 203 F.
They also refer to a Battery Temp. Sensor which sits underneath the Battery...this Sensor I have on my 2002 Export CRD and may be fitted on your 2004 model...definitely not on the 2005 and up models...not really relevant!

The two relays get +12 volts to pin #30 from Fuse #2 30 Amp..may be different on the 2004 KJ.

Pins #86 on both relays (relay coil) get +12 volts when ignition is ON.
Pin #85 gets grounded by the PCM C3 pin 4 for the High Speed Relay and pin 6 for the Low Speed Relay. Pin #87 on the relevant relay then supplies +12 volts to pin #3 on the Fan Motor (high speed) and pin #1 (low speed) on the Fan motor.

Re-plug Connector C3 on the PCM a few times in case there is bad contact on some pins.

Pin #2 on the fan motor goes to ground via a Black wire....make sure that this ground is good!

So check that both relays do get energized. The Theory Of Operation for the Fan Operation is very vague...they do not state if the Low Speed Relay gets energized first and then the High Speed Relay gets energized if things get hotter.

Swap these two Relays over in case one is faulty and see if symptoms change.

I suspect that maybe The Slow Speed Relay gets Energized and if things get too hot that the Slow Speed Relay gets dropped and the High Speed Relay gets Energized!

Either way you could fit a Switch to Pin #3 on the fan motor and to Ground to force the Fan into High speed (maybe) and a switch to Pin #1 on the fan and then to ground to force Low Speed (maybe).

You may have to have one Switch On while the other is Off!

And make sure your AC is switched ON while climbing your hills slowly!

Have fun!

 

[mduclow]

I was just out there running it. I pulled the low speed relay and within a couple of minutes or so after starting it up the fan came on. I thought that was odd as the temp gauge was only reading about 1/4, it was still warming up.

I pulled the High speed fan relay and plugged in the low speed fan relay and the fan did not come on, visual verification was made. I waited until it warmed up to the 1/2 line and no fan with only the low speed fan relay plugged in, and it wouldn't go over the 1/2 line after another almost 10 minutes of waiting. No fan.

I plugged the high speed fan relay in and unplugged the low speed relay, started it back up and the fan came on (still on the 1/2 line). I unplugged the high speed relay and the fan went off, plugged in the low speed relay into the high speed relay and the fan came on.

I also jumped #30 and #87 on the low and high speed relay connector, with both relays out it would only run the fan when the high speed connector was jumped, when the low speed connector was jumped the fan did not come on.

I finished by putting both relays back where they were originally and deduced the low speed on the fan is not working. As the low speed relay worked fine in the high speed relay connector, I am assuming the relays are both good.

Back to the original problem, if only the high speed is working on the fan motor wouldn't that ultimately be better than just the low speed, at least as far as cooling a hot motor goes? So where am I now on my cooling problem? Potentially a fan not even running at the proper speed when the high speed is on?

I'm leaning towards a new fan but want to hear what anyone has to say about this. I also intend to replace the coolant with the recommended for the vehicle, if only to check it off the list of possible contributors.

Marc

 

[mduclow]

I've also just stumbled upon the fact that this Liberty has the big shroud and threaded w/p pulley snout, but no clutch fan. I think it would be a good idea to add the clutch fan into this vehicles cooling system.


It looks like the e-fan needs replacing and adding in the clutch fan might be my first changes, along with making sure the recommended coolant is used. Best I can tell everything else seems good enough to start with those first.

Marc

 

[Billwill]

Is the speed of the fan and air flow higher with the fan running in High Speed mode?

I presume the fan is running in the correct direction ie. blowing and not sucking...nothing surprises me nowadays.

If you are getting a good air flow then the problem must be elsewhere ie. blocked radiator or the radiator fins are blocked with debris!

You can download the 2005 Jeep Service Manuals here...the descriptions of what could cause overheating will still be valid as regards the 2004 KJ. Also gives you the procedure of how to drain and re-fill the cooling mix and what percentage of red HOAT/ZENEX must be used with distilled water.

www.colorado4wheel.com/manuals/Jeep/KJ/

 

[mduclow]

I can't say for sure what speed the fan is actually running at, but with the hood closed and the car running it is noticeable enough in sound to easily tell it is running.

I think I want to do this one step at a time. It seems the e-fan is dying, and with 197,000 miles on it I'm betting the fan has never been replaced on this vehicle, or not in a long time at least. I'll replace that first and make sure to swap the coolant with Zerez G05. See where that leaves me.

To that notion, does anyone recommend an inexpensive electric fan upgrade? I'm looking at the Derale 18217, but there are some reviews that state it failed quickly after install. I'm not 100% sure It can be wired in correctly without some bushcraft technology added in, which I would rather avoid if possible. Which leaves me open to suggestions if anyone has any.

Marc

 

[Billwill]

You can try take the fan apart and lubricate all moving parts...I doubt that it is electrically bad but maybe the bush/bearings it runs in has gone bad.

A single-speed fan ie. only has two wires to it or one wire and a ground can easily be connected to the existing wiring ie. take power off the existing High Speed or Low Speed wiring.

A two-speed fan can be connected to the two relays but make sure you know which wire is the ground!

Make sure it turns in the correct direction....if the polarity is not correct it will go backwards!

The fuses may have to be upgraded slightly if the new fan draws more Amps....the existing relays should handle any extra power

 

[JeepJeepster]

If you have the bigger shroud then you can buy the fan clutch and blades so you have the HD cooling. I thought only the 2004's got the bigger shroud but it sounds like 2005 did also. If that doesnt lower the temps then you would know for sure you have something else wrong. FIY, its kinda tight getting everything in there when installing the mechanical fan.

I added the mechanical fan awhile back and like having the extra cooling and peace of mind that if the electrical fan fails, I still have cooling. With the already vulnerable 3.7's liking to drop valve seats if they overheat, I want to keep it cool. Only issue, I got the HD fan clutch and that thing ROARS. Im sure its hurting my performance and mpg... It'll eventually quieten down but if you just stop at a red light, it'll roar again for a bit.

Kinda odd, but I didnt notice the HD cooling fan lowering the transmission temps at all. The limiting factor must be the undersized factory transmission cooler. Maybe Jeep tried to 'get it just the right size' since it doesnt have a thermostat and they didnt want to overcool the transmission... They sure dont need to worry about that.... It gets over 200F quick when towing and Ive only towed short distances in the grand scheme of things. ~30min towing a 14' trailer loaded with mulch and it was at 230F.

 

[uss2defiant]

main cooling is always by the e-rad fan and not the clutch fan.

my thoughts are the same as Jeepjeepster with regards to the rad. Since you don't know how well it was taken care of in the past, most of the small passages is probably clogged preventing good cooling of your system.

the testing of the e-rad fan is to wrap some newspaper together as a bat and let the e-rad fan blade hit it. if it doesn't cause considerable stoppage then the e-rad fan is good.

My early model KJ uses PWM to control the speed of the e-rad fan.
Some members here have wired a switch to keep the fan on at the high speed when off roading.

It might be too late but you might want to see if the clutch fan followed the old engine and never got transferred.

 

[JeepJeepster]

main cooling is always by the e-rad fan and not the clutch fan.

This might have been the case from the factory but its not the case with the HD clutch. My engine hasnt gotten over 204F since adding the mechanical fan. Electric fan doesnt kick on till 217F in my KJ so other than kicking on with the A/C, its not been on since I added the mechanical fan.

Ive thought about getting a regular duty clutch just to see if I gain any mpg/power back.

 

[Billwill]

main cooling is always by the e-rad fan and not the clutch fan.

My early model KJ uses PWM to control the speed of the e-rad fan.
Some members here have wired a switch to keep the fan on at the high speed when off roading.

Which early model KJ used PWM to control the speed of the e-rad fan?

I am not doubting you but I would like to look into the Logics to see how this is done!

My early 2002 Export 2.5L Diesel came with only a clutch mechanical fan...I have long been thinking of fitting an electrical fan as the slightly newer 2.5L Diesels came fitted!

I have never had cooling issues on my Jeep though...I have recently drained and re-filled the coolant with distilled water and the correct amount of Mopar HOAT..so probably will not bother with sourcing an electrical fan now!

 

[uss2defiant]

I am not doubting you but I would like to look into the Logics to see how this is done!

per the 2003 service manual, it is controlled by the PCM(?) to a SSR.

I don't have a oscilloscope at home to verify it.