2019 Grand Caravan coolant thermostat question

[hamiltzp]

My wife's Grand Caravan just threw a check engine light, code P0128. I have read that 99% of the time, this is caused by a bad coolant thermostat. Looks easy enough to replace.

My dilemma is whether to go OEM or aftermarket. I've been watching a lot of Royalty Auto, South Main, and Pine Hollow, as well as a few others, so I know the opinion that professional mechanics have about crappy aftermarket parts. However, I REALLY don't like the plastic housing on the OEM. It just seems inappropriate and, well, cheap. 1A Auto has an aluminum one that I am tempted on. The housing would be superior, but I'm not sure about the quality of the functional thermostat part.

Also, thinking like the YouTube mechanics that I watch, I'm wondering if I should do some more diagnosis to confirm that it is, indeed, the thermostat. I don't know what more I would do, though.

Thoughts?

Thanks.

 

[D60]

Let it warm up ten minutes, drive it a couple miles then shoot the radiator or a metal coolant passage with an IR gun. I'm not sure if a rubber hose is a good indicator -- but maybe ok? It should read within ~10F of t-stat temp. Let it idle a couple minutes and it should still read close to t-stat temp. Pick the hottest point you can read on the cooling system and use that every time.

How does the heater work? If heat output is poor it's almost surely the t-stat.

Failing that, pull the stat and see if it's stuck open visually. You can also boil it and monitor with a thermometer, but at that point I'd install a new one ANYWAY.

I'm all for metal housings but I'd choose a quality stat in plastic over an unknown import in metal, if those were my options.

 

[dogememe]

Very common failure on the 3.6, sell many many many of them.

How much is the OEM part?

 

[D60]

Also, can't you call up water temp as an actual number on the dash? If that and IR gun mostly jive, and it's definitely lower than it should be after warming up, it's the stat.

 

[4wd]

https://www.chryslerminivan.net/

 

[Rand]

OEM, most aftermarket thermostats are almost always junk.

 

[hamiltzp]

Very common failure on the 3.6, sell many many many of them.

How much is the OEM part?

Both the OEM and the aluminum aftermarket are just shy of $50.

That and the oil filter housing are both plastic, and I really don't like that. At least with the thermostat, if it fails, it usually fails open so the engine runs too cool. My understanding is that if the oil filter housing cracks, I could be in deep doo-doo real quick.

Thanks.

 

[dogememe]

Both the OEM and the aluminum aftermarket are just shy of $50.

That and the oil filter housing are both plastic, and I really don't like that. At least with the thermostat, if it fails, it usually fails open so the engine runs too cool. My understanding is that if the oil filter housing cracks, I could be in deep doo-doo real quick.

Thanks.

I mean the aluminum aftermarket is a good idea in theory but it’s Dorman and the main rule of automotive is never trust Dorman. Haha.

Assuming the replacement part lasts 5 years… are you even going to have the car then?

 

[hamiltzp]

I mean the aluminum aftermarket is a good idea in theory but it’s Dorman and the main rule of automotive is never trust Dorman. Haha.

Assuming the replacement part lasts 5 years… are you even going to have the car then?

Ideally, yes. My wife likes it, and we tend to run vehicles into the ground. Look at the bottom of my original post and you'll see what I mean!

Supposedly the part is TRQ, which is 1A Auto's house brand. Of course, I don't know where they source them from. Come to think of it, does Dorman actually make Dorman?

 

[TnT_M]

My wife's Grand Caravan just threw a check engine light, code P0128. I have read that 99% of the time, this is caused by a bad coolant thermostat. Looks easy enough to replace.

My dilemma is whether to go OEM or aftermarket. I've been watching a lot of Royalty Auto, South Main, and Pine Hollow, as well as a few others, so I know the opinion that professional mechanics have about crappy aftermarket parts. However, I REALLY don't like the plastic housing on the OEM. It just seems inappropriate and, well, cheap. 1A Auto has an aluminum one that I am tempted on. The housing would be superior, but I'm not sure about the quality of the functional thermostat part.

Also, thinking like the YouTube mechanics that I watch, I'm wondering if I should do some more diagnosis to confirm that it is, indeed, the thermostat. I don't know what more I would do, though.

Thoughts?

Thanks.

We had this same issue on our 2014. I put the console on coolant temperature and it was significantly cooler than normal. I changed it with a genuine Mopar part almost 4 years ago. No issues with the plastic housing.

I did upgrade to the aluminum Doorman oil cooler a couple years ago.

 

[grasscutter]

That 1A Auto is probably a Dorman.

 

[wtd]

I would go with OEM and on two vehicles in our family that set that code, both times a thermostat fixed it. One was a 2008 Ford Focus and the other was a 2010 Chevy Cobalt.

 

[t1snwrbrdr12]

For what it’s worth we use 4 seasons brand on our 3.6 fleet at work (or at least the last box that I saw a brand on was 4 seasons, all the boxes lately still look the same without branding). They seem to leak before they even come due for their next service.

 

[KrisZ]

I don't understand the obsession over plastic components. So the plastic thermostat housing was fine for 7 years now, but when it comes to the replacement, it's somehow an issue? The logic simply doesn't follow.

Get the OEM one and don't worry about it.

Now, the plastic 'Y" connectors are another story. These are documented to fail at the least desirable moments, like a family trip, hundreds or thousands of miles away from home. These should be changed pro-actively.

 

[zzyzzx]

Can you get a metal aftermarket with a good brand like Aisin or Calstat?

 

[The_Eric]

Use both OEM coolant and stat.

Too many aftermarket ones fail early and why use another coolant other than OE? Using another formulation would mean flushing the system.

 

[hamiltzp]

I don't understand the obsession over plastic components. So the plastic thermostat housing was fine for 7 years now, but when it comes to the replacement, it's somehow an issue? The logic simply doesn't follow.

Get the OEM one and don't worry about it.

Now, the plastic 'Y" connectors are another story. These are documented to fail at the least desirable moments, like a family trip, hundreds or thousands of miles away from home. These should be changed pro-actively.

Plastic is just one more point of failure. In fact, in one of the how-to videos I watched on YouTube, the guy pulled his old thermostat off in pieces because one of the internal plastic tabs broke. I wonder if that thermostat itself was still good, but it was the housing that failed.

What are these Y connectors, and where are they? This is the first I'm hearing about this. I know about the oil filter housing, and I was thinking of changing that proactively.

 

[KrisZ]

What are these Y connectors, and where are they? This is the first I'm hearing about this. I know about the oil filter housing, and I was thinking of changing that proactively.

It's the heater hoses that have these plastic Y splitters that fail.

Rock Auto has a direct replacement with aluminum Y connectors from SKP and Dorman.
I tried changing just the connectors and it's a fiddly job because the original ones are permanent connection with no hose clamps, and it leaked anyways.
So just save yourself the aggravation and get the entire hose set.


Edit:
I checked my order and I got the SKP set and I also had an issue with this set leaking where it connects to the heater, because the clamps were not tight enough. I had to get a tighter set of clamps. So perhaps get Dorman.



https://www.rockauto.com/en/moreinfo.php?pk=13560281&cc=3309782&pt=6892&jsn=663

 

[The_Eric]

The issue with the metal housings and fittings from companies like skp or dorman isn't the housing,it's their absolute garbage rubber o-rings. Sure the housing or fitting won't fail, it'll just leak like a sieve in a year or 2

 

[michaelluscher]

OE Mopar or Mahle off RockAuto (depending on availability)