Odd temp issue (problem?)

[JackieRedShoes]

Hello there!

05 KJ sport, 222k, owned since Aug 2015 @ 203k

Brought it to a dealer shortly after I bought it for 2 recalls and a cooling system flush, however I'm not certain the dealer actually flushed it... What color is the coolant a Jeep dealer uses?

Replaced the radiator twice under warranty from 1-800, once before the "flush" and once after, thermostat also during the latter, and a heater core after that.

I paid $900 for the Jeep, managed an independent repair garage and bought it from a customer, so I had about 2 years of service records. Being over 200k, it didn't surprise me that it burned some oil and coolant would "disappear," so I just checked both regularly and it drove and warmed me just fine all winter, until...

About 2 weeks ago I was sitting in it with it idling for a couple hours, and it overheated. I recall that it was fine for several hours while I had the heat on low, but shortly after I turned the blower off completely is when the coolant in the reservoir was boiling and spitting out from either the reservoir cap or the bottom front hose coming from the reservoir. Let it cool, filled the reservoir while it was running, let it run some more, drove around and everything seemed fine for about a week, and my commute is 60+ miles each way 4-5 days/week.

Backstory:
(So after reading all this stuff on this site about HOAT coolant shortly after I bought it is why I decided to have the dealer flush it. However, when the radiator and thermostat were replaced after the flush, I almost got in a fight with my mechanic who insisted that "normal" coolant will not cause any problems, and eventually got him to agree to trade me his 04 Grand Cherokee for my Liberty if he was proven wrong.)

Back to now:
So after a normal week and several hundred miles, it started to overheat again, and again it was shortly after I turned the blower off after idling for about an hour. Let it cool, topped it off again, but now comes the "odd" issue (problem?)

City driving everything is as it should be, but when highway driving the temp gauge goes from the middle DOWN to about a quarter, and the heat stops...well... heating...

Today I noticed the reservoir cap seemed to be looser than it used to be, so I replaced it with one I found in the Jeep when I bought it that fit much tighter and appeared to be in good shape, but again on the highway the temp gauge goes down and I lose heat. Otherwise it still drives and runs fine, but I don't want to just ignore this because the weather is getting warmer and I won't need the heat. Again, once I get off the highway the temp gauge goes back to "normal" and the heat gets warmer.

While on the highway today I turned the blower up, down, on, off, temp up and down but nothing changed. It's not blowing smoke and the oil looks fine so I don't think it's a head gasket.

I've searched this site for info and I'm wondering if it's the water pump. I hope it's not the water pump. Tomorrow I'm going to get a brand new reservoir cap and keep my fingers crossed.

I hope it's not the water pump.

Any other ideas?

Thanks in advance

 

[Conundrum2006]

The radiator fluid I though looked orangish, someone else said more redish, but not green or yellow.

Did the dealer do the thermostat too? It almost sounds like the thermostat is stuck open, getting too cool on the interstate , then warming back up.
Or it's a circulation issue, but it ought to overheat in the city and highway if it were.

You should be able to tell if it's got pressure when its running at temp hoses ought to feel like they have pressure going through them.
I'm new to the 3.7 jeep so I'm not sure what the water pumps do when they fail. I've heard some stories but no first hand experience.

BTW the thermostats for these vehicles are extremely finicky, got to be Mopar, well at least it's more reliable.



Sent from my iPhone using Tapatalk

 

[uss2defiant]

Here are my questions:

1. Is your e-radiator fan working properly?

OPERATION
The electric radiator cooling fan is controlled by the Powertrain Control Module (PCM) through the radiator cooling fan relay. The PCM regulates fan operation based on input from the engine coolant temperature sensor, battery temperature sensor,air
conditioning select switch and vehicle speed. The fan is not energized during engine cranking regardless of the electrical input from the temperature sensors and ,air conditioning switch. However, if engine operation conditions warrant fan engagement, the fan will run once engine starts.

Vehicles Equipped with AC:
In addition to using coolant temperature and battery temperature sensor to control cooling fan operation, the cooling fan will also be engaged when the ,air conditioning system is activated. The relay is also energized when, air conditioning is selected and coolant temperature is above 95° C ( 203° F), or , air conditioning is selected and battery temperature sensor is above 41° C (106°F). It will then de-energize when , air conditioning is selected and coolant temperature is below 92° C (198° F), or , air conditioning is selected and battery temperature is below 38° C (100° F).

2. was your t-stat replaced with a mopar one?

3. are you loosing coolant? have you pressure tested your system?

4. is your water pump weeping for the weep hole?

Note that mixing different coolant is bad. Possible sludge. may also cause water pump damage. you might be winning that Cherokee after all.

 

[JackieRedShoes]

New reservoir cap today and it's doing the same thing. The fan works as it should and both hoses do have pressure.

The thermostat was from API which usually means Mopar but I'm not certain. It doesn't seem to be leaking anywhere today but I don't have a way to pressure test it today without having to pay.

Interestingly enough, the new reservoir cap is different from the one that was on it that went bad. The old cap was definitely leaking because I used to smell the coolant that dripped from it on the manifold and now there's no smell and everything is dry.

It's looking more like my tstat is stuck open as Conundrum suggested, which makes sense.

The reservoir cap was likely leaking a little ever since I've owned it, which explains the vanishing coolant and smell, and when I did pressure test a while ago everything else was holding just fine. If that's the case, the cap finally just got worse and made it overheat, causing the tstat to stick open, which is why it only really acted up on the highway.

Gonna throw a new tstat at it and see how she does. Anything better than Mopar that I would likely be able to find on a Saturday at places like Napa/Advanced/AutoZone?

Thanks for the input!

 

[uss2defiant]

you can get a pressure tester from your local autopart store's tool loan program.
test it at 16 psi.

get a tstat from the dealership if you're adamant about getting it replaced today.

 

[JackieRedShoes]

Right.

If I don't fix it today and drive a couple hundred miles over the weekend, think that could cause more problems?

 

[uss2defiant]

yeah... that's your call on that.
I think it's either the tstat or waterpump or both.
If the WP hasn't been replaced yet, it might be a good PM thing to do.

My WP was from NAPA.

Godspeed

 

[Conundrum2006]

Napa has a very good water pump. I think they call it true flow.


Sent from my iPhone using Tapatalk

 

[JeepJeepster]

If the temp is dropping down on the hw then the thermostat is bad. That could be causing all of your issues with the 'random overheating.'

Buy a mopar thermostat and a mopar radiator cap. Go from there

And find a new mechanic. You cannot mix regular green coolant and hoat coolant.

Edit: if you want it now a super stant from advance auto seems to be good. I wouldnt get a regular stant.

 

[renegade 04]

If you go with the Napa water pump always go for the ultra premium, and I also know that Napa has gates water pumps!

 

[uss2defiant]

If you go with the Napa water pump always go for the ultra premium, and I also know that Napa has gates water pumps!

There's only one brand of WP that napa sells for libertys.

 

[JackieRedShoes]

Going to drop it off at a shop near where I'm working today and have them put a new thermostat and pressure test it. If I recall correctly the water pump was replaced not too long ago.

More will be revealed.

 

[renegade 04]

I had to replace mine twice before I finally got a Water pump that did not leak. If you replace the water pump make sure that you torque all the bolts to factory spec!

 

[dude1116]

The radiator fluid I though looked orangish, someone else said more redish, but not green or yellow.

Did the dealer do the thermostat too? It almost sounds like the thermostat is stuck open, getting too cool on the interstate , then warming back up.
Or it's a circulation issue, but it ought to overheat in the city and highway if it were.

You should be able to tell if it's got pressure when its running at temp hoses ought to feel like they have pressure going through them.
I'm new to the 3.7 jeep so I'm not sure what the water pumps do when they fail. I've heard some stories but no first hand experience.

BTW the thermostats for these vehicles are extremely finicky, got to be Mopar, well at least it's more reliable.



Sent from my iPhone using Tapatalk

Orange or yellow. Mopar and Zerex, respectively.

 

[JackieRedShoes]

Well I had the thermostat replaced yesterday and drove about 140 miles, mostly highway, and the temp gauge is acting normal and the heat works great again. Hoping that now with a new reservoir cap as well, the cooling system will function as it should and I won't lose coolant anymore. Fingers crossed!!!

Thank you all for the input! And I seem to have found another HOAT coolant that I don't think I've seen mentioned here, Pride Universal. Check it out:

(First time trying to add pics, not sure if it's going to work. If not let me know and I'll try to fix it)

 

[tommudd]

Well I had the thermostat replaced yesterday and drove about 140 miles, mostly highway, and the temp gauge is acting normal and the heat works great again. Hoping that now with a new reservoir cap as well, the cooling system will function as it should and I won't lose coolant anymore. Fingers crossed!!!

Thank you all for the input! And I seem to have found another HOAT coolant that I don't think I've seen mentioned here, Pride Universal. Check it out:

(First time trying to add pics, not sure if it's going to work. If not let me know and I'll try to fix it)

Universal scares me right off sure its HOAT?? or advertised as being HOAT compliant or some BS?
Personally would NOT use that
Hope you did not add that

 

[uss2defiant]

looks like it may be hoat from the website.??
idk
PrideUniversalGold34

 

[JackieRedShoes]

If you click the pics the front says hybrid organic silicate and the back lists several specific Chrysler engines, one of which is my Liberty

 

[tommudd]

If you click the pics the front says hybrid organic silicate and the back lists several specific Chrysler engines, one of which is my Liberty

I clicked on the pictures, I read, I looked, I then looked away :shrug::icon_lol:
I'll stick with going to Napa

Digging into it more to see whats in it for sure,

I have heard the term " compatible" many times over the years when some company was trying to sell something that just was on the edge of working but not quite there.
Reading up some more when I have a chance , but its not like Zerex is uber expensive to buy so............:shrug::emotions34:

I see it does match ASTM D 3306 but nothing about Chrysler MS9769,

Hybrid Organic Acid Technology (HOAT)

 

[uss2defiant]

Tom,

The pdf spec sheet mentioned CHRYSLER MS7170, MS9769.
http://www.prideantifreeze.com/assets/pride_universal_antifreeze_v021015.pdf

But what is throwing me off is the document saying all truck specifications require
“Fortifier” Additive*

What additive is not mentioned.

Here's a list of vehicles that are mentioned in the pdf

AUDI, BMW, MERCEDES BLATT
325-0, 325-2
CAT DEAC, ELC
CHRYSLER MS7170, MS9769
CUMMINS 90TB-4, CES4603,
CES14603
DETROIT 7SE298, POWERCOOL,
POWERCOOL PLUS
FORD WSS-M97B51A
FREIGHTLINER 48-22880
GM 1899M, 1825M, 6277M
GSA A-A870, A-A 52624
JLCASE 501
J DEERE H24 A, B, C, H-5
MACK O-A 5450
MTU MTL5048, MTL5049
NAVISTAR B-1, I,II,III
PORSCHE TL-774C, 774D
SAAB 6901– 599
SAE J814, J1034, J1901
TMC/ ATA RP302, 329, 338
TOYOTA (pre 2010)
VOLVO, VW G-11, G-12