Overheating

[AVKO]

Curious if anyone has any ideas...

Early January I noticed my coolant temps rising while towing my SxS in sub zero weather. Took my pickup in and they cleaned the thermostat and radiator since they didn’t have any replacement thermostats in stock.

Seemed to work better for awhile but started to run hotter even when not towing. Took it in again and they replaced the thermostat which was about a month ago.

Just got back from a fishing trip to Canada pulling my SxS and the temp would periodically rise. Now it seems to do it more consistently, especially when idling.

Think it’s the thermostat again or something else? Only coincidence that I noticed is that the temp seems to decrease the more I get into it.

Thanks for any ideas.

2015 6.4L 2500 Big Horn 67,*** miles


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[Ratket]

I’ll bet money someone mixed in the wrong coolant. As in mixed Hoat with Oat.

 

[Rampant]

x2 ^^^

 

[AVKO]

Thanks for the ideas.


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[Ratket]

I would flush all the coolant out with water, may take 2-3 times before it is cleared of all coolant, double check ur owners manual and refil with proper coolant at the proper mix rate for your temps. Does the 2015 take Hoat like the 2014? Or did they change it? Look at the invoice and see if it says what type of coolant they used, or go by the shop and ask them what they use. It could be the thermostat, but two bad in a row is odd, have you checked the coolant lvl? Maybe it needs to be burped?

 

[AVKO]

My manual calls for OAT and the invoice didn’t state what they added. I have an appointment tomorrow and will update afterwards.


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[Ratket]

I swore the 6.4 took Hoat, but I have been wrong before, I don’t have my 6.4 anymore, but can you double check ur owners manual one more time?

 

[G. Mcpherson]

What! No 2500 6.4? When did this happen.

I swore the 6.4 took Hoat, but I have been wrong before, I don’t have my 6.4 anymore, but can you double check ur owners manual one more time?

 

[Ratket]

Like I said I could be wrong lol

 

[WilliamS]

Does it only rise when idling or stopped at a light or do you notice it while cruising?

 

[AVKO]

I’ve noticed it when cruising also. Just picked it up from the dealership and they replaced the radiator. On my way home temps rose to 240 again while idling. They bleed and drove it so they don’t think it’s air. Guess there’s not much else except the water pump.


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[Ratket]

What coolant are they using?

 

[AVKO]

I never asked and the invoice didn’t state. I have another appointment scheduled for Friday.


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[Ratket]

Keep us posted.

 

[TMyers]

I don't know about the Hemi's cooling system but the 6.7 Cummins will hold air pockets. After flushing and adding new coolant, drive it a little while then recheck the level. I added nearly 1/2 gallon after the initial refill over the course of 3 days.

 

[AVKO]

Well...I get to go back on Monday. Tech spent some time talking with Chrysler’s engineers to come up with a solution. They think it’s some control module which will be delivered Monday. Guess we’ll know more then.


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[AVKO]

Well...so far 0 for 5. They replaced the PCM with the same result. They are waiting to hear back from the engineers.


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[AVKO]

I would flush all the coolant out with water, may take 2-3 times before it is cleared of all coolant, double check ur owners manual and refil with proper coolant at the proper mix rate for your temps. Does the 2015 take Hoat like the 2014? Or did they change it? Look at the invoice and see if it says what type of coolant they used, or go by the shop and ask them what they use. It could be the thermostat, but two bad in a row is odd, have you checked the coolant lvl? Maybe it needs to be burped?

As of now it looks like you win. Like I mentioned earlier they replaced the PCM without any luck. Water pump checked out. IR thermometer near coolant temp sensor showed 180 while engine at 230. Replaced temp sensor with no luck. Checked wires to temp sensor and they checked out. Checked bus wires from PCM to IPC and they checked out. Ultimately flushed the system until clear with cleaner and put new coolant in. Temps on my way home seemed ‘normal.’

Hopefully this solved the issue. Thanks everyone for your suggestions.


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[Ratket]

I’m gonna be honest, if this is the case, I would just get rid of it. Once the build up begins it most likely won’t stop and will haunt you in the future. I would look at images on the internet of what happens when you mix Hoat and Oat coolant. You never know who put what in there.