what is the deal with the 180 T-Stat, everyone has one but I cant undestand what they do... people say it makes "engine more efiicient" but it just seems that it dissipates heat (if you are talking thermodynamic effciency), which has nothing to do with effiency if you are reffering to heat generation in an "Otto Cycle" because heat is generated from friction and dissipating it has nothign to do with the pistons moving.
Also I have heard that a lower T-stat puts a heavier duty cycle on your pump and even sometimes has the reverse effect because the coolant doesnt spend enoguht time in the radiator to absorb the heat (not sure if I believe the last one).
Or am I completely wrong?

The purpose from what I can recall is to keep the engine temps cooler. When trying to run higher levels of HP, you are able to get/ and keep the power that you want.
This helps to fight heat soak, and the engine oil temps run at a lower level aswell (10* lower on mine).


On a N/A motor, when its colder the motor performs better.

what is the deal with the 180 T-Stat, everyone has one but I cant undestand what they do...
The lower t-stat will richen your fuel mixture a bit (at the expense of gas mileage), increase your exhaust emissions (at the expense of our poor planet) and will dirty your oil faster. As an added bonus, it will shorten the life of your cylinder walls and catalytic converters and foul the spark plugs sooner. But wait, that's not all - it will also play havoc with your heater temps in the winter and may trigger codes.

^ Don't forget coolant spray too! :p

People have had thrown codes in the winter because of a t-stat?

This is new to me... Who has experienced this personally? I have read alot about what people think about the t-stat, and the effects it had on their trucks. I havent come across someone that says engine codes are thrown in cold weather.

I would like to know more about this. :)

^ Yes, if they used the 170 instead of the 180. It's in the big thermostat thread. ;)

The lower t-stat will richen your fuel mixture a bit (at the expense of gas mileage), increase your exhaust emissions (at the expense of our poor planet) and will dirty your oil faster. As an added bonus, it will shorten the life of your cylinder walls and catalytic converters and foul the spark plugs sooner. But wait, that's not all - it will also play havoc with your heater temps in the winter and may trigger codes.

Party pooper;)

The lower t-stat will richen your fuel mixture a bit (at the expense of gas mileage), increase your exhaust emissions (at the expense of our poor planet) and will dirty your oil faster. As an added bonus, it will shorten the life of your cylinder walls and catalytic converters and foul the spark plugs sooner. But wait, that's not all - it will also play havoc with your heater temps in the winter and may trigger codes.

I propose an easy solution. BUY A JET 180* T-STAT. The 170* stat obviously causes problems. So many people use the 180* and it seems to be working well for them.

Lesson learned.... stay away from 170* T-Stat

Ooh 1 more thing, This thread is for a 180 t-stat.... Then Y post negative info on a 170* T-stat, especially if hardly anyone uses them anymore

I have a jat T-Stat I got with my predator, but my buddy who is a 3rd generation mechanic (his dad and both brothers have shops so he is fairly knowlegeable) warned me against it, he said he will put it in for me but I should really look into why. I thought about it and I do agree with the denser fuel mixture but I do not buy that it makes the motor efficient, people seem to say it but nobody know why...
I think people confuse colder temp with efficiency; a more efficient motor will not make as much heat (ie less friction) but a colder motor doesn mean its more efficient, or people would just put lots of fans around the motor, right?
I like the reply from ResumeSpeed, right on guys thanks I think I will skip.

I have a jat T-Stat I got with my predator, but my buddy who is a 3rd generation mechanic (his dad and both brothers have shops so he is fairly knowlegeable) warned me against it, he said he will put it in for me but I should really look into why. I thought about it and I do agree with the denser fuel mixture but I do not buy that it makes the motor efficient, people seem to say it but nobody know why...
I think people confuse colder temp with efficiency; a more efficient motor will not make as much heat (ie less friction) but a colder motor doesn mean its more efficient, or people would just put lots of fans around the motor, right?
I like the reply from ResumeSpeed, right on guys thanks I think I will skip.

imo... i have always been around the old school push rods... the cooler the better, i dont think it is to hard to see that... HOWEVER with todays technology i think motors are made to run at a higher them...

if my 289 gets above 190 i am freakin out... but then again ford's always ran on the low side...

but to answer your question... it is all thermodynamics... (i would like to BS the answer and say "why do you worry about having cold air going in if your engine heat is higher, by the time it ignites youll be hot again...")

The law in Thermodynamics I think you are talking about (regarding to heat) is Entropy. Entropy is related to heat... blah blah blah, long story short when there is conbustion and the gas expands the less the change in Entropy (isoentropic expansion I believe) the more efficiency.
I dont think any T-Stat can have any effect. Again I think it just dissipates the heat created it does not do anything for the actual efficiency of the motor. I am not sure if I corerect though, its been a while since I took tests on this stuff! I guess I can bust out the book... but whatever after what ResumeSpeed mentioned I dont think 180 T-Stat is for me

The law in Thermodynamics I think you are talking about (regarding to heat) is Entropy. Entropy is related to heat... blah blah blah, long story short when there is conbustion and the gas expands the less the change in Entropy (isoentropic expansion I believe) the more efficiency.
I dont think any T-Stat can have any effect. Again I think it just dissipates the heat created it does not do anything for the actual efficiency of the motor. I am not sure if I corerect though, its been a while since I took tests on this stuff! I guess I can bust out the book... but whatever after what ResumeSpeed mentioned I dont think 180 T-Stat is for me

i was trying to not get to technical... and i hated thermo... (i was more of a machine design kinda guy)... anyway i think this hit it on the head... if it dissipates heat... the block will be cooler, making the combustion chamber slightly cooler... like i said in my 289 i can tell it hits a damn wall at 190... doesnt want to idle correctly etc etc (only happens in traffic on hot days though)...

with that being said i still have a stock t-stat (i am just playing devil's advocate with science)... i think that it is one of those "this rock is harder then that rock" if it does help, it might drop me .02sec... but is it worth possible problems (coolant shooting everywhere etc etc)

I HATE the thermostat. Yes, I used caps! But I did notice that the engine ran cooler. But the coolant spray wasn't a trade off I was willing to "pay" for it.

Well, to actually answer the question about performance..... when the engine runs hotter it pulls timing out. Therefore, a cooler engine will run more timing and produce more power. I believe if it's over 195-200* then that's when timing gets pulled and the hotter it is, the more timing is pulled. I've had mine in for 30K now with no issues. no fouled plugs, no clogged cats(Wait, I don't have any:D), fuel milage....:rofl: it's a 6.1L HEMI for Christ's sake, there is no fuel economy. I've never had a code triggered, and my heater worked just fine last winter. Please explain your reasonings RESUME..... how could an engine running 15-20* cooler hurt the cyclinder walls? Grip Grip has about 110K on his and it seems to be running pretty strong. I don't think you give our motors the benefit of the doubt.

Please explain your reasonings RESUME..... how could an engine running 15-20* cooler hurt the cyclinder walls?

+1, i can see the richer mixture fouled cats and spray / codes, but what is it about running the cooler stat that will affect the cylinder walls?

also the OP asked about the coolant pump duty cycle.. is that affected at all?

oh ya you are KILLING your pump! I had a 180 T-Stat on my old dodge dakota 4.7 and it did run cooler, dont know if I noticed the power gains. I think if the temp is such an issue (timing, fuel mixture...) why dont they come stock with 180? Is it because of emissions? Also going back to thermodynamics and the 4 stroke engine cycles, i dont think making an engine cooler gives it efficiency, all motors have a target temp where they are at their peak; its just a matter of where it is for our motor, I would think they'd figure it out during design, no?
I also think in ars there are many variables, its easy to cling to a few good points but there might be other things going on that are not as obvious.

but again... I am not a car person, I cant even drive well!!!

Someone correct me if I'm wrong but, our water pumps are mechanical not electrical correct? What difference does it matter to the water pump if we have a different thermostat? It's spinning the same regardless of engine temps.

hmmm, dont know, if that is the case then I am wrong (that is assuming the coolant is always under pressure regardless if it is flowing or not). That would suck if the pump is always spinning seems like a waste huh

i think you're right harrison, if i remember right it's belt drive.

Yeah I had a feeling I was right about this one. It's all one belt that runs off the crank. It doesn't know any different.

hmmm, dont know, if that is the case then I am wrong (that is assuming the coolant is always under pressure regardless if it is flowing or not). That would suck if the pump is always spinning seems like a waste huh

Yeah it is a waste of power for sure. That's why alot of big motor cars run electric water pumps so you're not robbing power from the engine to spin it.

About the spray....
I have the same ammount of spray issues that I had stock.

When the truck was stock I took it to the dealer and complained about the coolant spraying all over the place, and they couldnt fix the issue.
So I figured maybe a new t-stat and a 18lbs stant locking cap will help, since the stock coolant system likes to spray all over the place I figured, it couldnt hurt.

So after I changed the parts I noticed slight coolant spraying.... but it only happens occasionally... like 1 time in the past 2 months
But it did that when it was stock...

I dont see where I sacrificed coolant spray for the cooler temps, especially if I had an issue when it was stock...



-oooh and P.S.
I do remember the SRT engineers saying they used a "hotter" than 180 t-stat for the truck to help with emissions

Aparently the 6.1 Hemi is hard to get to pass factory emissions testing :)

I wonder if anyone has tried switching to the 2007 coolant resv.? It seems that 07's don't do it. I know Hawkman's 06 does it pretty bad. Anyone have an 07 that's spraying?

I used to have a 180 on my RT (5.7L) for 3 years and it always ran hot (like stock) after half an hour of driving anyway, so I went back to putting in a stock thermostat last week.
I'll keep it stock on my future GCSRT8, I won't bother, I think the Hemis runs hot by design so there's no point IMO.
Sorry for being negative, but after 3 years of personal experience that's how I feel about it.
Furthermore, I never felt any HP or throttle response improvements, the only thing that improved my throttle response and kept my HP when the engine was hot was a true CAI like Volant, best intake I've ever used on my RT, all the other tube/filter intakes I had killed my performance and throttle response when the engine was hot.
On the other hand, I drive city 99% of the time, so I guess a 180 mod might work well if you drive often on the highway, where the airflow will keep it at 188-190, but in my case with all that city driving I found it to be useless.

The t-stat topic will be debated forever, with an endless amount of opinions both for and against. In my own experience running the stock thermo, my best times at the track have been my later runs - when the engine temp has been the hottest. That seems to be in direct contradiction to many other SRT8 owners (Jeep/300C/Charger/Challenger) who have reported gains at the track of a tenth or two running a low stat with fan control. Personally, I'm happy with the numbers I get running stock, a tenth or two matters not.

For those that insist on running a lower t-stat, there are a couple of important points to note - if you are not using some type of fan mod, then you are wasting your time as your engine will not run much cooler. Second, you need to occasionally run your engine up to full operating temperature to flash away contaminants and moisture in the oil (!!!!).

The t-stat topic will be debated forever, with an endless amount of opinions both for and against. In my own experience running the stock thermo, my best times at the track have been my later runs - when the engine temp has been the hottest. That seems to be in direct contradiction to many other SRT8 owners (Jeep/300C/Charger/Challenger) who have reported gains at the track of a tenth or two running a low stat with fan control. Personally, I'm happy with the numbers I get running stock, a tenth or two matters not.

For those that insist on running a lower t-stat, there are a couple of important points to note - if you are not using some type of fan mod, then you are wasting your time as your engine will not run much cooler. Second, you need to occasionally run your engine up to full operating temperature to flash away contaminants and moisture in the oil (!!!!).

Agree with you on this one.....particularly about the "never ending debate.

I've been running the 170 for a few years now. About 85+ % of the time, according to the gauge it will run 185-190. I will allow it to occasionally run up between 200-215 in stop and go in town situations to do exactly what you said....."flash away contaminants". Than switch on fan mod (for 2-4 minutes only) to pull it back down to the 185 or so area. Usually with AC on, and some unobstructed air while just cruising, it holds that 185 number unassisted by the fan mod.

Just my experience and I probably have a mental disorder that makes me like to see that lower reading...:)

To this point my oil reports from Blackstone as evidenced in my recent post points to everything being good with no evidence of moisture or other contaminants.

I will say occasionally it will throw a code. Maybe 2% of startups if I do not warm it up and drive it in a certain pattern for the first few minutes. Such a small percentage of the time though that it does not bother me to clear it.

Just my thoughts and experience.

I run the 180 with no codes, I believe that the choice of stock t-stats has more to do with passing emissions more than anything else

As far as coolant spray my buddy's stock Jeep was almost identical to mine when I bought it and he was spraying a crazy amount of coolant. I thought the little I had was bad until I saw his.

One thing that I discovered was that leaving the reservoir closer to the low level reduced my coolant spay to next to nothing

Resume.... can you elaborate on the cyclinder walls being worn faster by running a lower T-Stat? I've never heard of that before......

Im an 07 owner who put in the 180 t-stat that you had to shave down to fit and constantly got coolant spray about 2 weeks ago I finally put in the Jet 180 and another new 18lb locking cap. This time I only put back in HALF of the coolant that I caught in the zip lock bag my coolant resevoir is probably only a 1/4 full WELL BELOW that blue mark. I have beat the poop out of the jeep since then, been to the track, hwy rolls etc and not one drop from the cap or anwywhere. When I took out the old t-stat it was in the stuck open position (after sitting all night) which tells me it was a bad t-stat and constantly flowing fluid and most likely making alot of pressure in the system I also would suspect those with the Jet 180 getting spray may have installed it wrong you have to make sure the bleeder valve is on TOP when you put it in.

Im an 07 owner who put in the 180 t-stat that you had to shave down to fit and constantly got coolant spray about 2 weeks ago I finally put in the Jet 180 and another new 18lb locking cap. This time I only put back in HALF of the coolant that I caught in the zip lock bag my coolant resevoir is probably only a 1/4 full WELL BELOW that blue mark. I have beat the poop out of the jeep since then, been to the track, hwy rolls etc and not one drop from the cap or anwywhere. When I took out the old t-stat it was in the stuck open position (after sitting all night) which tells me it was a bad t-stat and constantly flowing fluid and most likely making alot of pressure in the system I also would suspect those with the Jet 180 getting spray may have installed it wrong you have to make sure the bleeder valve is on TOP when you put it in.

Yeah I have to agree with you Wade. I just installed my Jet 180 and the Stant 18 lb cap, and adjusted the fan settings in the Predator and I have you spray at all. I also lost a little coolant on the install and only put back in what I was able to catch in the ziplock bag. I also made sure the the whole coolant system was bled and up to operating tempature before I put the cap back on. So far I have noticed the level in the Reserve tank is a lil lower and I have not had any spray at all in the last 2 weeks. Plus I drive my Beast like I stole it so it should have sprayed by now if it was going to do it.

Seems to be working Jose

The t-stat topic will be debated forever, with an endless amount of opinions both for and against. In my own experience running the stock thermo, my best times at the track have been my later runs - when the engine temp has been the hottest. That seems to be in direct contradiction to many other SRT8 owners (Jeep/300C/Charger/Challenger) who have reported gains at the track of a tenth or two running a low stat with fan control. Personally, I'm happy with the numbers I get running stock, a tenth or two matters not.

For those that insist on running a lower t-stat, there are a couple of important points to note - if you are not using some type of fan mod, then you are wasting your time as your engine will not run much cooler. Second, you need to occasionally run your engine up to full operating temperature to flash away contaminants and moisture in the oil (!!!!).


Ha ha it seems there is lots of debate about a little part that has not proven to do anything, but has been know to couse problems. I still dont get how physically it makes a car engine more efficient besides the fact that it possibly allows colder/denser air to enter the intake manifold. Also the problems of emissions is enough to keep me from installing mine!
I think this is one of those controversial parts that people get because they see others listing them as their mods and they are cheap and the vendors claim "more horsepower". Like I said, I had a 180 T-stat on my dodge truck, never had problems but also never felt any improvement, the gauge did read cooler but I am not sure that is a good thing; i do not thin cooler is alsways better, otherwise our mototrs would have better cooling systems from the manufacturer (why not put a freezer next to your block)...? It might be good for some cars but not others, all deppends on many variables I think, not sure if it better or worst for our cars.

I had a 180 in my charger and now in my jeep. Occasionally when its cold out, i'll throw the code about coolant temp not being where hal wants it. My jeep sits right at 200* once it warms up. I never had an issue with either and since my jeep is an 09, no coolant spray issues either.
As a side note, there is only one part number for the coolant tank for all 06-09 WK's and it's the same tank that is in the 08-09 but doesn't leak. Hops23 has an 08 and had his tank replaced, looks identical but no leaks.

I had a 180 in my charger and now in my jeep. Occasionally when its cold out, i'll throw the code about coolant temp not being where hal wants it. My jeep sits right at 200* once it warms up. I never had an issue with either and since my jeep is an 09, no coolant spray issues either.
As a side note, there is only one part number for the coolant tank for all 06-09 WK's and it's the same tank that is in the 08-09 but doesn't leak. Hops23 has an 08 and had his tank replaced, looks identical but no leaks.

It's all the same part # b/c there is an updated one which is the new style. If you were to buy a new one it would be the 08-09 style. I know when I popped my hood on my 07 vs. Dave's and Chris' 06, they were different.

Seems to be working Jose

Yeah Wade. Thanks for posting up them fan settings a while back! They worked out great!

I wonder if anyone has tried switching to the 2007 coolant resv.? It seems that 07's don't do it. I know Hawkman's 06 does it pretty bad. Anyone have an 07 that's spraying?

my 07 sprays from the stock rad cap. not much though.

For those that insist on running a lower t-stat, there are a couple of important points to note - if you are not using some type of fan mod, then you are wasting your time as your engine will not run much cooler. Second, you need to occasionally run your engine up to full operating temperature to flash away contaminants and moisture in the oil (!!!!).

i'm not using a fanmod. my coolant temp sits at 190 cruising at 70. it shoots up when idling in place, but if i want to bring it down i turn on the heater or AC for a minute or two.

as far as flashing away moisture, i guess that happens when the oil temp rises above the boiling point of water (212F) which happens all the time.. i don't think there's an issue w/ that.

It's all the same part # b/c there is an updated one which is the new style. If you were to buy a new one it would be the 08-09 style. I know when I popped my hood on my 07 vs. Dave's and Chris' 06, they were different.

I know, just posted that up for people with the older style to not expect the same one if they get it replaced. ;)

I wonder if anyone has tried switching to the 2007 coolant resv.? It seems that 07's don't do it. I know Hawkman's 06 does it pretty bad. Anyone have an 07 that's spraying?

I have an 06 and it doesn't spray ever, even when running the road courses.

I have an 06 and it doesn't spray ever, even when running the road courses.

Maybe certain Jeeps just don't like their owners.:lol: This whole ordeal of spraying is just baffling. You've got STOCK Jeeps that do it, thermostatted Jeeps doing it, thermostatted Jeeps that DON'T do it...... it's just plain weird!:shrug03:

I thought we already went through this? I know I've said this several times. Allow me to repeat again...

The 06-07 varies and most of the time a stant radiator cap prevents it altogether. Us 2008+ guys have it stock and the thermostat intensifies it!

http://i496.photobucket.com/albums/rr326/BlackJeepSRT/af793dd0.jpg

http://i496.photobucket.com/albums/rr326/BlackJeepSRT/d1a3e919.jpg

I thought we already went through this? I know I've said this several times. Allow me to repeat again...

The 06-07 varies and most of the time a stant radiator cap prevents it altogether. Us 2008+ guys have it stock and the thermostat intensifies it!

http://i496.photobucket.com/albums/rr326/BlackJeepSRT/af793dd0.jpg

Damn! That is bad man! Is that your Beast? Have you tried the Stant 18 lb cap yet?

^ Am I going to have to choke a *****?

thats terrible

My spray issues are nothing compared to that. I would invest in a 18lbs stant cap if I were you...

Are you both a bunch of idiots? Seriously. You don't think I actually tried that? Guess what? I did! And guess what? It didn't work. Guess what again? I tried keeping low coolant too. You guessed it, that didn't work either. Fans, yup, tried that too.

But do you know what did work? Taking that **** out!

Calm down there Tiger! The reason we both asked you was cuz we did not see the Stant Cap in the picture. Plus we have not been on every 180 Tstat thread and knowwaht you have done in the past.So calm your s**t down homie! We didn't mean any harm. Laterz

No harm, just stupidity. I've been on here longer than you and have dealt with it. I was probably one of the few to actually bring this to the attention of the SRT Engineers at the past few chats and for you both to say that is... for the lack of better word, silly.

No harm, just stupidity. I've been on here longer than you and have dealt with it. I was probably one of the few to actually bring this to the attention of the SRT Engineers at the past few chats and for you both to say that is... for the lack of better word, silly.

Its all good man! We are all here to help each other out thats all. Oviously the Stant works for some and for others it doesn't. Cool!

So, you've obviously come across this secret mod referred to as the "stant" but I, only being here for 13 months, never came across it? :lol: You guys are funny. Really.

I am very sorry to hear about your frustrations with spray.
I would be too if I was in your situation.

Your spray issue is VERY bad.
But in my situation the stant cap helped. I didnt see it in your pic so this is why I made the suggestion

I'm going to have to search about this secret mod nobody has even mentioned since I graced this forum 13 months ago. How do you guys know about this, but not me? :lol:

It has since been fixed. By putting the stock on back in.