temp gauge says overheating but it's not

[justhelplz]

Jeep Lib. Sport '03. 3.7 138k, well maintained. temperature gauge went up had thermostat replaced. when I give it gas, gauge goes up heat falls off but idling its giving heat. no milky oil no obvious coolant leaks. Does not appear to be overheating. mechanic said over the phone its a head gasket and wants to use Blue Devil, I need more information, does anyone know anything about this, thank you.

 

[ltd02]

Is the coolant level and water pump okay? Is the tstat in backwards? Is it the correct coolant? Wouldn't go putting anything in until it was better diagnosed. Best to replace the HG if it is the culprit. Are you actively losing coolant out the tail pipe or into the oil? Is coolant boiling over from the tank? Many many questions...

 

[belvedere]

Like ltd02 said, you need to do some diagnosis. I would start with pressure testing the cooling system. It could be a head gasket, but I wouldn't jump to conclusions.

 

[LibertyTC]

^ Good recommendations.
Just by the title, I get the feeling the OP does not want to agree with his temp gauge.
You can plug into the obd2 post to confirm the coolant temp.
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An OEM Mopar thermostat is the only one I would install, and pressure and water pump test is your best approach.
I just hope you have not been driving it long, in these conditions.
Driving the Jeep at real high temps is asking for a blown head gaskets or worse.

 

[CactusJacked]

Do as ltd02 suggested first, checking the coolant level. Especially since the t-stat was replaced, make sure all the air is bled out of the system, bleeder fitting is on top of the upper water neck. A little fyi, the temperature sensor reads coolant temperature, not air temperature. So if the coolant level in the engine is low (not contacting the sensor), the temperature gauge will not read correctly.

 

[justhelplz]

Tstat not in backwards, will check tomorrow if water pump has been replaced ever. Regular antifreeze in it, levels look fine. Not boiling over. Will check a few things tomorrow.

 

[uss2defiant]

what is this regular antifreeze you speak off?

 

[justhelplz]

50/50 prestone or some brand. Is that not right?

 

[M38 Bob]

Before all the "HOAT" ******** starts, even that devil piss Prestone installed new wouldn't cause the OP's issue.

Since Dodge and Jeeps are related I will mention a case my Son ran into last week. An 01 Ram 1500 with fluctuating temp gauge. Ended up having two heat sender switches, one to gauge, the other to computer. Replaced them both and the gauge became reliable again.

Bob

 

[uss2defiant]

The coolant temp sensor is right in the middle of the engine. I think it's right under the air resonator box if you have one or right behind the Ac compressor and alternator in the middle.

could try to just replace that.

btw,prestone isn't the right coolant.

 

[justhelplz]

Thank you all. I am a woman and not a mechanic, and I have cried all day. I will check tomorrow everything I can, and research where to get these diagnostic things done. I'm not driving it. But will check in tomorrow.
The time is wrong on mine, it is 1:06 AM, not 6 AM

 

[justhelplz]

What is the right coolant?

 

[uss2defiant]

if there's a harbor freight close by or an autopart store, you could buy an OBD2 reader like what LibertyTC mentioned to at least eliminate or find out whether it's the engine coolant temp sensor.


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[ltd02]

What is the right coolant?

Correct coolant is this type Mopar HOAT or Zerex G-05. These don't mix well with the green Prestone stuff.

50% this with distilled water or just get the 50/50 premix.

Link: Buy Valvoline Zerex ZX G-05 AFC ZXG051 at Advance Auto Parts

They often have this stuff at Napa and sometimes Pepboys too.

 

[M38 Bob]

What is the right coolant?

HOAT

See section 5.4 https://en.wikipedia.org/wiki/Antifreeze

Suitable brands are; MOPAR original equipment, Zerex G05, and an economy version often found in dollar/discount stores "PolyFreeze" Gold Global.

While HOAT is the only recommended antifreeze formulation, this is for long term cooling system durability. No 50/50 mix would come close to causing the issues you're describing.

Bob

 

[LibertyTC]

justhelplz, there is no reason to cry. Any good mechanical shop can help to get your cooling system checked & performing correctly.
It is good that you joined the forums as we have all had to learn much about the Jeep Liberty (KJ) and it is a bit particular regarding fluids and specifications.
Your owners manual can become your friend when it comes to operation and what types of coolant, gear lubes, transfer case, power steering requirements etc.
If you do not have an owners manual, you can get a free pdf from owners section, on Jeep site (2004 will work) link: Jeep Owners | Download an Owners Manual 2004 - 2011 | Jeep
Most of the original water pumps had a plastic impeller, and when non Hoat coolant products were used, damage to the water pump's impeller was possible.
I would highly recommend since the system now contains the wrong coolant, that a flush of the system, be performed after any mechanical issues have been checked or repaired.
The Jeep dealer has the correct recirculating machine to perform the entire flush, and will ensure Hoat and distilled water is used for a proper mixture.
The dealer's machine will remove all of the wrong coolant which is what you want to do now.
For the system to operate correctly, it must be leak free, and the water pump working well, thermostat opening at the correct temp 195F with the coolant level correct, free from air pockets ( Air bleeding once full using top rad hose bleed screw)
The Hoat coolant type will last 5 years and I always let the Jeep dealer do the coolant flush. I think I paid around $150 for this job in Canada, so it may very well be cheaper in the USA.

 

[justhelplz]

Ok. I'm going to ask that instead of bringing the Blue Devil to pour in my coolant, he bring an obd2. Is there any other diagnostic things that can be done in my driveway? He said he bled the air after the tstat.

 

[LibertyTC]

Look at coolant reservoir is it at the cold line? If not, add some to fill to cold line.
Is the engine light on? If so use obd2 reader, key set to on but engine not running to diagnose pull codes, post em back.
Pressure test reservoir, see if it will hold 16psi, look for any coolant leaks.
Inspect oil dipstick for bubbles/ milky off color looking oil.
When temp is at half way mark on gauge or 200F+ on reader, is the top rad hose soft or hard, squeeze gently, feel coolant going through?
Look at rad electric cooler fan does it come on? To engage engine cooling fan you can turn the selector all the way to right to defrost mode, Ac clutch should engage and the fan should be on turning.
If the thermostat is stuck in the open position it will set a code, Mil light, for too long to warm up.
If the thermostat is stuck in the closed position, the jeep will heat up too high, and eventually set a warning as well, don't let temps climb that far!
Or if the pump is not pumping too well, the temps will climb high as well.

 

[CactusJacked]

Did anybody else notice in the video above (2:37 mark), where they say to "refill the reservoir using the proper type of coolant", and proceed to pour in Prestone.
Or maybe they had an empty jug and just used it for mixing...yeah that's it!

 

[renegade 04]

I have learned that unless you can get a digital read out of the coolant temperature, that the only way to get a accurate reading. Just a fyi that the factory temperature gauge will not show that your are overheating until it is too late. I happen the know this because I have a digital aftermarket coolant temperature gauge.