Running a little hot at idle...

My second post here - new member and new Liberty owner. 2002 Sport with the V6.

Vehicle runs dead-center on the temp gauge while driving, but slowly starts to creep up when stopped and idling. Hasn't even come close to overheating, but I'd still like to see it stay cooler....

Previous owner said he replaced the radiator within the past year. No coolant leaks to be found (no leaks of ANY kind, actually!).

I've read that using the wrong coolant can damage the water pump vanes, reducing efficiency and possibly causing the heat buildup. I have no idea what coolant is in the system.

What about air in the system? I'll probably bleed it to see, but wondering if that would cause it to run slightly hot as well.

Water pump is a cheap and easy fix if necessary, but looking for other possible causes to avoid unnecessary work.

Thanks!

E fan kicking on? Do you have the mechanical fan? Could be worth replacing the clutch - but an 02 should be ok I'd think. I just replaced the factory one my 96 XJ last year.

Water pump sounds like a good starting point. Make sure to get HOAT/ Zerex G05 in there!

I hate to admit that I haven't checked the fan. Sheesh. Yeah, that'll be job one. Thanks!

Swap the fan relay with another one like it.

I’ll be checking the fan operation in the next day or two.

The 02 has a two speed electric fan. The fan switch is located below the battery

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Well the fan is working. I’m not sure about dual speed, but I ran the engine and the fan is definitely functioning. I opened the coolant reservoir and it looks a little muddy in there. I think a flush and fill with known proper coolant is next ...

HoosierJeeper said:

Swap the fan relay with another one like it.

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Can't do that with a '02,newer KJ's with the 2 speed fan yes but not the older with 1 speed.

rjkj2005 said:

The 02 has a two speed electric fan. The fan switch is located below the battery

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"02's use a single speed fan and that relay is for a Grand Cherokee not a Liberty.

Get the updated one from the dealership.

I wonder if the replacement is a mopar rad, which is the best to use.
Living in Arizona, you want the best cooling possible.
Once again do you have only the electric fan or a clutch based too, some pics would be nice..
How many miles on this KJ now?
If the water pump has not been replaced a new one for sure. Even new Upper & lower rad hoses & a new thermostat.
The dealership has a re-circulating machine and does the best flush, it gets all the old crap out, & their proper mixture... will be HOAT coolant. Not overly expensive for a proper flush.
Tap water should never be introduced into system.
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I cant rely on the middle or so for a temp gauge.
I like the Mini scan gauges that will report exact OBD2 temp readings.(Fwt)
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The fan comes on around 227 F? Cant remember now but it is up there.

Based on my scan gauge the fan kicks on in fast around 225° in my '05, which is noticeably to the right of center on the dash. My fan is 2 speed and a while back the low speed relay crapped out, that only the second time I had seen the fan kick on in high due to the coolant temp. Replaced the relay and it hasn't happened since. I'm not sure what temp it kicks on in low. I'm going to wire to LED's to indicate when it kicks on, just so I can monitor proper function.

Joenavy85 said:

Based on my scan gauge the fan kicks on in fast around 225° in my '05, which is noticeably to the right of center on the dash. My fan is 2 speed and a while back the low speed relay crapped out, that only the second time I had seen the fan kick on in high due to the coolant temp. Replaced the relay and it hasn't happened since. I'm not sure what temp it kicks on in low. I'm going to wire to LED's to indicate when it kicks on, just so I can monitor proper function.

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That's a cool idea. Probably gonna copy it with the led.

I’ve only got the electric fan ... no mechanical. Can’t be sure if the radiator is Mopar, but I’d assume not. 175,000 miles on the truck. I’m going to start with a flush & fill and go from there. Water pump looks like a simple job, and something I’ll do in the near future if not immediately.

My 04 kicks the low speed on at 218... Not sure about the high speed.

After adding the mechanical fan the engine hasnt gotten over 205F.

With the dual fans is the efan still two speed? Or is it single?

I've never seen my temp gauge go past one tick below center, knock on wood.

I remember one summer day pulling the boat back late in the afternoon, it was 100F.
Jeep with A/C on & only electric fan going full tilt, was reading 250F.
I decided to pull over with it running and lift the hood, it was like getting hit by a blast furnace!
It's amazing how fast the temps dropped with the hood open back to 225F.
It's a shame Jeep did not give us a larger rad or more ventilation/some hood vents.
I'm really not into cutting up the hood though.
Maybe leave the hood at home? Ha Ha..

TC you should get the mechanical fan! I remember one time when I was wheeling in Tennessee with some LOST people and 3/4 of us had the dual fans, one guy and the single efan and we had to stop a few times to let it cool down. The dual fan peeps were just fine sitting in the AC.

Yes Thanks HJ, are those parts still available new- shroud/clutch fan?

LibertyTC said:

Yes Thanks HJ, are those parts still available new- shroud/clutch fan?

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they are on rock auto. i bought the shroud and efan and fan blade from ebay for cheap and got the hayden clutch from rockauto.

Well I don’t exactly know what the specific problem was - water pump, thermostat, coolant, air in the system ... but it’s all been dealt with and now running great. New pump, new thermostat, proper coolant, and a good air purge after everything, and I’m sitting a just a hair below center on the temp gauge, even sitting at idle with AC on full tilt. Easy DIY, and cheap insurance for the hot summer ahead.

Awesome. Glad to hear it!!! Get that thing off road now.