Chrysler 300C & SRT8 Forums banner
1 - 17 of 17 Posts

·
Registered
Joined
·
13 Posts
Discussion Starter · #1 ·
I see that changing to a 180ºF thermostat is reccommended. I'm curious as to how much this will help with increasing performance. What are some pro's and con's for changing out the thermostat? Also, what would be a part# from like advance auto parts or something. Are all thermostats interchangeable? I see that 203ºF is OEM but how would I choose the right one for a lower temp.
 

·
Premium Member
Joined
·
3,499 Posts
Helps avoid engine heat soak which robs power.
180*F = Auto Zone #4128.
All thermostats are not interchangeable.
While lowering the t-stat temperature will help lower the engine temperature in most normal driving conditions to get the full effect the cooling fan temperatures should be similarly lowered.
 

·
Registered
Joined
·
44 Posts
Lowering the operating temperature of today's "Street Engines" will offer no power increases and in the long run shorten engine life!!:pat:

The OEM design specs are for emissions, performance, fuel economy and longevity and all of these will suffer by forcing lower operating temps for "Street Applications"!! :sad:

We've hashed all of this out for several years on other forums and the consensus is "spend your $$'s elsewhere" unless you are racing!!:)
 

·
Premium Member
Joined
·
633 Posts
Changing the thermostat seems to be the cheapest way to gain some performance with these cars. It is the first thing I did after I received my Predator! Could not be happier. Lowering the engine temperature apparently effects a sensor or two (= computer not pulling timing) and additionally helps keep the intake air ducts cooler which all help with the performance. Our cars love cold air in the intake ducts.

Desiree, above gives the best advice.

Coosawjack, please tell us how lowering the engine temperature will effect the longevitiy of my engine? I have not read, seen or heard how that can happen.

Emissions? I know of several people who have passed their state's emission tests with alternate thermostats installed. So how is it a problem?

But, anyway dude, if you don't want to change your thermostat, no problem, but be careful about telling everyone that their emissions, engine life, mileage and performance will be worse, I don't agree.

So we have "hashed this out" ON THIS FORUM, and for the $15 I spent on the 4128 and the 15 minutes I spent installing it, IT IS A NO BRAINER! If you do not want to file just a small bit of metal off the 4128 edges to get it to fit, then buy the Jet Thermostat for a few dollars more and it drops right in and comes with a new gasket.

The con's on the deal?? Don't know of too many. Some guys leave the 170 degree thermostat in for the street and get the dreaded check engine warning because the engine has not warmed up to the programmed operating temperature after a set number of starts. You should avoid that thermostat for the street (but it is great for the strip and really hot weather), but the 180 or 185 degree units work fine. I keep the 185 degree thermo in year around in Minneapolis and have NEVER got a warning light. I have driven it in -20 to -30 degree weather.
 

·
Premium Member
Joined
·
932 Posts
Lowering the operating temperature of today's "Street Engines" will offer no power increases and in the long run shorten engine life!!:pat:

The OEM design specs are for emissions, performance, fuel economy and longevity and all of these will suffer by forcing lower operating temps for "Street Applications"!! :sad:

We've hashed all of this out for several years on other forums and the consensus is "spend your $$'s elsewhere" unless you are racing!!:)
The same subject has been hashed out here for years and while the conclusion is not unanimous, I would say a majority here agree that a colder thermostat gives a minor benefit in horsepower and is worth the minor expense and is easy to install. There is no reason to expect reduced longevity, especially in the 5.7L which uses 5W-20 oil. I suspect that the high stock temperature yields a minor fuel economy benefit which is important to the corporate CAFE rating but negligible to the owner. So feel free to run your stock thermostat, you will still have a fast car and will probably not notice that tenth of a second in the quarter mile.
 

·
Registered
Joined
·
44 Posts
The same subject has been hashed out here for years and while the conclusion is not unanimous, I would say a majority here agree that a colder thermostat gives a minor benefit in horsepower and is worth the minor expense and is easy to install. There is no reason to expect reduced longevity, especially in the 5.7L which uses 5W-20 oil. I suspect that the high stock temperature yields a minor fuel economy benefit which is important to the corporate CAFE rating but negligible to the owner. So feel free to run your stock thermostat, you will still have a fast car and will probably not notice that tenth of a second in the quarter mile.
Agreed!!:)

Another forum I'm on has batted this around a long time and the consensus is that our modular aluminum engines benefit (however small) from running at design temps......my Marauder is 195-210 degrees and 180 degree stat is ONLY beneficial for detonation control in blower cars with aggressive timing!!

I don't know about the Chrysler engines but expect they are about the same from an engineering standpoint??

BTW, I have 220K miles on my original 4.6 Liter engine in my Marauder with the last 135K miles supercharged.....still STRONG and uses no oil but that's another chapter in my "insanity" book!!:pat:
 

·
Premium Member
Joined
·
932 Posts
Coosawjack,

Note that a cooler engine block = a cooler intake manifold & underhood temperatures = a denser intake charge = more horsepower. Why else would someone ice their intake manifold at the strip. In a previous thread I calculated that ideally the temperature drop would give an additional 15 hp or thereabouts but since I suspect one probably would not get the full theoretical increase, I estimated and increase of 5 to 10 hp. What is so special about these motors that requires them to run hotter than other manufacturer's motors? 180 thermostats are common enough in other motors. And just curious, what makes our motors "modular aluminum engines"? I thought our motors were just plain old cast iron blocks with aluminum heads.
 

·
Registered
Joined
·
122 Posts
yes, this horse has been beat beyond death...the t-stat effects the engine the same way an aftermarket airfilter does. some anticipated HP gains, better performance, etc, etc. The key here is nothing has been thoroughly documented nor evidence provided to give us concrete figures. it is widely accepted both will offer better throttle response. anything beyond that is purely speculation. start your car in the morning note the acceleration response and consider the same response after operating at stock temp. there's a clear difference. probably more obvious in an srt8 vs any other engine offered. i've heard consistent positive comments on the jet 10183. the tstat reduces the other "well-documented" throttle lag at operating temps above 220*
 

·
Premium Member
Joined
·
3,202 Posts
I use the Jet 180* t-stat (part JET #10183). I got it at Amazon.com for $30 with free shipping. It came with the gasket, fits perfectly, and never throws codes. Expect a small improvement in performance from the lower operating temp.
 

·
Registered
Joined
·
44 Posts
yes, this horse has been beat beyond death...the t-stat effects the engine the same way an aftermarket airfilter does. some anticipated HP gains, better performance, etc, etc. The key here is nothing has been thoroughly documented nor evidence provided to give us concrete figures. it is widely accepted both will offer better throttle response. anything beyond that is purely speculation. start your car in the morning note the acceleration response and consider the same response after operating at stock temp. there's a clear difference. probably more obvious in an srt8 vs any other engine offered. i've heard consistent positive comments on the jet 10183. the tstat reduces the other "well-documented" throttle lag at operating temps above 220*
Cold start will give you a rich fuel/air mixture and better throttle response to a point...WOT will suffer greatly with a cold engine!!

I have never heard of anyone accurately measuring any power gains from an air filter or thermostat change....SOTP will show gains because you want them!!

Another note...."Modulars" are what Ford has used for awhile and I guess I thought the Chrysler motors were too.....are the blocks iron.....I have not checked that?? Mod motor bearing clearances are much tighter and materials are different, thus temp "sweet spot" is higher.......and they require thinner oil.... I run 0W20 in mine and have 90 PSI cold idle with 25 PSI hot idle....FWIW??:rolleyes:
 

·
Registered
Joined
·
688 Posts
So Coosawjack, you don't actually have a 300 that you've listed as your car under your user name?
 

·
Registered
Joined
·
44 Posts
So Coosawjack, you don't actually have a 300 that you've listed as your car under your user name?
Yes, we actually have the 300C and I have an '04 Dodge RAM with a 5.7 HEMI but never considered the block material being iron....but they are pushrod motors aren't they??

My Marauder is my DD though!!
 

·
Registered
Joined
·
3 Posts
Cold start will give you a rich fuel/air mixture and better throttle response to a point...WOT will suffer greatly with a cold engine!!

I have never heard of anyone accurately measuring any power gains from an air filter or thermostat change....SOTP will show gains because you want them!!

Another note...."Modulars" are what Ford has used for awhile and I guess I thought the Chrysler motors were too.....are the blocks iron.....I have not checked that?? Mod motor bearing clearances are much tighter and materials are different, thus temp "sweet spot" is higher.......and they require thinner oil.... I run 0W20 in mine and have 90 PSI cold idle with 25 PSI hot idle....FWIW??:rolleyes:
Interesting.
 

·
Registered
Joined
·
24 Posts
I use the Jet 180* t-stat (part JET #10183). I got it at Amazon.com for $30 with free shipping. It came with the gasket, fits perfectly, and never throws codes. Expect a small improvement in performance from the lower operating temp.

did you use and sealant on the gasket or just installed as is just ordered my tstat and gasket from amazon
 

·
Premium Member
Joined
·
3,202 Posts
did you use and sealant on the gasket or just installed as is just ordered my tstat and gasket from amazon
I just had it installed at the shop while they were changing my oil, so I don't know if any sealant was used. Maybe someone else who did the install can answer your question.
 

·
Premium Member
Joined
·
3,999 Posts
did you use and sealant on the gasket or just installed as is just ordered my tstat and gasket from amazon
No sealant is needed. It's a nice snug fit. Make sure the little nipple thing on the tstat is oriented to the top when you install it.
I just had it installed at the shop while they were changing my oil, so I don't know if any sealant was used. Maybe someone else who did the install can answer your question.
Look at that - 4 year old thread gets resurrected and the guy without a 300 gives a quick response! lol Bravo! :biggrin:
 

·
Premium Member
Joined
·
5,718 Posts
Its impressive how many old threads have been appearing lately.
 
1 - 17 of 17 Posts
Top