Thermostat lifespan?

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HoosierJeeper

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Getting ready for a road trip (about 600 miles round trip plus some off roading) in my Liberty next month and I got to thinking about the thermostat. I have 165k on it and the tstat is the original (every other cooling system part has been replaced, radiator, hoses, WP) I don't have any symptoms of it failing (still warms up quickly). I've read about replacement tstats (even Mopar ones which are Motorads) being finicky and sticking and people having to test them before installing and going through 2 or 3 before they open right.

So on one hand I feel like it might be foolish to swap a seemingly good one for a wildcard new one and on the other hand, I could see an old one being an issue at some point and overheating this engine usually spells death.

Any thoughts? Thanks!
 
Never had an issue with genuine Mopar thermostats.Nor with Gates,but CST ones act very strange.I'm sure Stant is ok too.
 
My Hyundai ones got lazy. Al thought they maintained the 180F opening temp for the most part they seems to be slow to warm and in the winter would drop below 180F when coasting. Put new ones in and they run at around 185F to 190F now. Should be better for winter.

One had 150k miles the other 80k miles. Both had same Tstat.
 
OEM thermostats are always a little more expensive, but you also expect (and normally get) an appropriate increase in reliability and quality control for the investment. The extra money you spend on an OEM thermostat is pennies compared to the cost of being stranded just once far from home and your tools. JM2C.
 
If I replace it, I'll definitely go Mopar...along with a new housing. Thanks for the brand advice.

I guess my question is, do tstats have a service interval for replacement? I haven't gotten any codes for it (like I did on my LR3 when its was sticking) and I don't know if I'd rather take a trip with a new tstat or an old but proven one...
 
The oe mopar stats are junk. Mine stuck open @ 24k. Dealer warantied it and that one didnt make it to 50k. I put a mopar one in and it was stuck by 75k. Been using stant and robertshaw ever since.
 
It seems like the safest option here would be to buy the thermostat of your choice and pack it, along with extra coolant and a tool kit. That way you won't be stranded IF old faithful gives out.

As far as replacements go, I used a Stant thermostat when I changed the water pump on my Silverado. It didn't look as robust as the stock piece, but has been working for the past 35k miles.
 
Originally Posted By: Chris142
The oe mopar stats are junk. Mine stuck open @ 24k. Dealer warantied it and that one didnt make it to 50k. I put a mopar one in and it was stuck by 75k. Been using stant and robertshaw ever since.


+1

OEM Mopar Stats used to be made by Stant, now they are made by Motorad and quality has dropped. I maintain 3 different Jeep Cherokees with the 4.0L. All of them, including my own, have a Stant 195* Superstat and function just as the factory did.
 
OEM parts are usually really good, except any OEM part from Chrysler/Fiat....

That should tell you something about how their cars are built.
 
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I like Chrysler stuff, obviously.
laugh.gif

Sounds like I should go with a Stant then. I am going to replace it before winter, regardless but do you guys think I can make the trip ok with the OE one?

Going to be down a vehicle the next few weeks so kinda need the remainders to be driveable and I'm not sure if I'll have time to replace it before the trip.
 
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Originally Posted By: Vern_in_IL
OEM parts are usually really good, except any OEM part from Chrysler/Fiat....


Especially crankshaft position sensors.
If you REALLY want to thump the beehive, go to any Jeep/Mopar/Fiat site and even mildly suggest an aftermarket crankshaft position sensor for your Jeep 4.0 inline.
Man, do the feathers get ruffled and the blood pressure rises!
(Even though Mopar/Daimler/Jeep/Fiat has never made an OEM Jeep 4.0 crankshaft position sensor that was worth a flip, the new FACTORY REPLACEMENT crankshaft position sensors are made in China, and I've personally had a few fail before they were in use for a year)
And before the Mopar loyalists get on my case on this site, yes, I know there are some bad aftermarket replacement cps parts out there.
 
I am starting to believe the [censored] thermostats sticking open issue is part of an unintended auto industry-planned obsolescence campaign. OEM's aren't going to spend time and effort sourcing high quality parts whose failure only leads to poor performing heaters and long-term issues like premature sensor failures and intake carbon build-up. Anecdotal evidence suggests even the premium brand's OEM stats are failing prematurely on an almost clockwork regular basis. Typical owners may never know they are driving a car constantly running below optimal operating temperature. They just go buy a new one after the maintenance hassles become too much.

I must be some sort of conspiracy theorist.
 
In my experience working on consumer cars, all thermostats (OEM or aftermarket) can last for hundreds of thousands of miles, or fail early.

Bottom line: There are no guarantees, so plan accordingly.
 
Originally Posted By: Rhymingmechanic
It seems like the safest option here would be to buy the thermostat of your choice and pack it, along with extra coolant and a tool kit. That way you won't be stranded IF old faithful gives out.

As far as replacements go, I used a Stant thermostat when I changed the water pump on my Silverado. It didn't look as robust as the stock piece, but has been working for the past 35k miles.


THIS^^^^
 
Originally Posted By: UberArchetype
I am starting to believe the [censored] thermostats sticking open issue is part of an unintended auto industry-planned obsolescence campaign. OEM's aren't going to spend time and effort sourcing high quality parts whose failure only leads to poor performing heaters and long-term issues like premature sensor failures and intake carbon build-up. Anecdotal evidence suggests even the premium brand's OEM stats are failing prematurely on an almost clockwork regular basis. Typical owners may never know they are driving a car constantly running below optimal operating temperature. They just go buy a new one after the maintenance hassles become too much.

I must be some sort of conspiracy theorist.


IDK, it seems to me like something they'd get right so they don't have to pay for repairs to California cars under their unduly long emissions warranty. And cars do throw codes for "running cool." When such a simple cheap part matters so much they should get it right. Look at how they basically forced iridium plugs via said emissions warranty.
 
Originally Posted By: HoosierJeeper
The Stant ones get bad reviews on Amazon....hm.


Are they Stant Superstats?
 
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