Dodge Durango 3.6L P0128 code

wwillson

wwillson

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2014 Durango 3.6L with 130,000 miles threw a P0128, which is "coolant did not reach operating temperature quickly enough".

I believe the cause is almost certainly a faulty thermostat, which I'm going to replace. I haven't researched thermostats for 20 years, so at this point I know nothing about them. Would you replace with OEM or is there a better aftermarket thermostat and why?
 
KrisZ said:
Definitely OEM thermostat, and they are priced quite well.

Also changing the plastic crossover to an aluminum one may be a good idea given the miles.

Click to expand...

That's an informative video - thank you!

Unless the crossover tube is leaking, I'll just replace the thermostat. The Durango thermostat and crossover have very easy access, so replacing a non-leaking crossover doesn't make sense.
 
OEM thermostat waiting to be installed. part # 0518-4651-AH

A055B383-A4A1-4066-9F83-EECE320EF70A.jpeg

3806783B-9D94-4D80-937F-14A0162BB05C.jpeg
 
KrisZ said:
Wow, that was quick
Click to expand...
My friend Bill got it for me in about an hour. I was surprised too, but he does a lot of business with the supplier and they deliver to him.

KrisZ said:
What coolant is in it? 2014 is near the crossover year I think, so be careful as Chrysler’s PHOT and OAT formulas are quite disastrous when mixed.
Click to expand...
I have not heard that, but will certainly check the manual. Will "any color" coolant work?
 
wwillson said:
My friend Bill got it for me in about an hour. I was surprised too, but he does a lot of business with the supplier and they deliver to him.


I have not heard that, but will certainly check the manual. Will "any color" coolant work?
Click to expand...
Highly recommend using the specified coolant. FCA has some odd issues with coolant mixing; their formulas seem to be unusually incompatible.
 
The Critic said:
Highly recommend using the specified coolant. FCA has some odd issues with coolant mixing; their formulas seem to be unusually incompatible.
Click to expand...
Not to mention that it seemingly changes colors depending on the cycle of the moon or whatever and looks like the other type of coolant sometimes. The purple coolant in my 300 looked orange when viewed through the side of the reservoir.
 
The tstat in my wife’s Town and Country 3.6 Pentastar went bad at around 98k, so for whatever reason this sounds like a thing.

I cheaped out and got an AutoZone one - not sure who made it - and burped it back up with “universal” coolant. Bad idea? Maybe. She’s at 103k and so far no problems. I drove it 1300 miles the day after I got it changed and burped, it acted fine as wine, temps stayed at their normal ~200*, and didn’t seem to have any other issues, even as I got up north where the lows were in the 40s at the time. Maybe I’m begging some problems, but we want to downsize anyway, so I wasn’t finna be that picky about it.
 
I put the new thermostat in today, which is a very simple job that took about 15 minutes. The intake runner covers the work area, but the runner comes off by loosening two hose clamps and unhooking a wiring harness. At 130,000 miles there was little if any corrosion or coolant mud in the system. OAT coolant was used for top-off per the urging in this thread.

It is surprising to me the old thermostat wasn't open when cold. It must open at a much lower temperature than it should. I burped the system and drove around for a while. The temperature gauge now goes quickly to the normal range and stays there. Before the temperature gauge took a long time to reach anywhere close to normal and now I realize it hasn't run at the normal temperature for a long time, like a couple years.

Engine bay before

Engine bay before


Intake running removed

Intake running removed


old thermostat closeup

old thermostat closeup


old thermostat closeup 2

old thermostat closeup 2


old thermostat removed

old thermostat removed


no corrosion

no corrosion


no corrosion 2

no corrosion 2


no corrosion 3

no corrosion 3


new thermostat

new thermostat


air intake clean

air intake clean

 
Cruising down the interstate today at 40°F the oil temp was where it should be. With the original thermostat, the oil temp would have been about 160°F, which is too cold. The Durango had a bad thermostat almost since new. I wish I had realized the issue and replaced it long ago.

20211017_121045924_iOS.jpg


I will make an update in this thread and eat some crow:

Covering Durango grille in winter to raise engine oil temperature

I cover most of the grill on my Durango in the winter to reduce the air across the radiator, in an attempt to get the oil temp above 165F. Below 165F the oil pump is always on the high pressure side and above it's on the low pressure side. I see no need to run around constantly with 90 pounds of...
bobistheoilguy.com
 
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The thermostat is a common issues with MOST late model cars today. It seems I am doing a quite few thermostats a month and most are on 3.6 GM and 3.6 Pentastars. My wife has a 14 Jeep GJ with the 3.6. I did her thermostat somewhere around 90k miles due to the P0128 code.
 
I'm having the P0128 code right now on my 3.6L in a 2013 Ram 1500 with 90K miles, on a warm day coolant temp was 185 when spec is 194. It took two start cycles for the check engine light to come back on after I erased the code. Problem is the factory replacement is $152 and autoparts models, generally deemed junk, run $15-$20. Someone suggested a Napa brand but they all look alike and I am wondering what the difference is from a factory replacement. Is there no quality thermostat to be had for say, $30 or $40? I really can't see spending $150 on a 10 year old truck for a part we used to spend $5 on to last a decade or so. Since my summer time temps have historically run 217-220 thinking I might just leave the old one in until next winter. I have noticed a little less heat a time or two but have plenty for south Texas.
 
brentwasham said:
I'm having the P0128 code right now on my 3.6L in a 2013 Ram 1500 with 90K miles, on a warm day coolant temp was 185 when spec is 194. It took two start cycles for the check engine light to come back on after I erased the code. Problem is the factory replacement is $152 and autoparts models, generally deemed junk, run $15-$20. Someone suggested a Napa brand but they all look alike and I am wondering what the difference is from a factory replacement. Is there no quality thermostat to be had for say, $30 or $40? I really can't see spending $150 on a 10 year old truck for a part we used to spend $5 on to last a decade or so. Since my summer time temps have historically run 217-220 thinking I might just leave the old one in until next winter. I have noticed a little less heat a time or two but have plenty for south Texas.
Click to expand...
Take a look at Mopar 68174083AA and see if it is correct for your pickup.

1676948990670.jpg
 
zrxkawboy said:
Take a look at Mopar 68174083AA and see if it is correct for your pickup.

View attachment 141373
Click to expand...
Mopar site says doesn't fit, must be for the V8. Mine comes installed in the housing. Several mechanics are saying OEM required to prevent failure so there must be something different about it. Illustration of the correct (68322748AA) Mopar part did look different than the motorad.
 
brentwasham said:
Mopar site says doesn't fit, must be for the V8. Mine comes installed in the housing. Several mechanics are saying OEM required to prevent failure so there must be something different about it. Illustration of the correct (68322748AA) Mopar part did look different than the motorad.
Click to expand...
Looking a bit closer, it looks like it fits the 3.7V6/4.7V8.

Wow, the Mopar stat for yours is spendy! Hope you find a suitable alternative.
 
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