Thermostat

[dpnewfie]

Is there any reason why I shouldn't install a 180 deg stat in this thing? I know the normal temp range for a N* is 195-215 but I was wondering if there was any benefit to running a N* cooler?

[myfirstbonnie]

The thermostat will not make it run cooler unless the fans are programmed to come on sooner. All the thermostat does is allow the coolant to start flowing at a cooler temp. Once all the coolant has heated up, the fans and radiator are what will keep it cooler.

[dpnewfie]

Ahhhhhh, silly me.

Thanks.

[SLOGXP]

Although this is a bit older post incase others are to read this the reply is not totaly true. A lower degree thermnostat will indeed let the car run at a cooler tempature reguardless of the fan temp setting. The thermostat is what controls the emgine temp / coolant flow. It was thought to remove a thernostat would make acar run cooler but not so in most cases. Being the thermostat is removed the flow of the water is increased and therefore does not have enough time to cool down in the radiator section.

Installing a lower thermostat is not always a good idea as the engine relies on center temps for emissions, sensors for fuel injectors ect. If you put a lower thermostat in the engine will think there is a problem with warm up and try to compensate with the fuel mixture, hence poor fuel milage and performance.

Its best to keep the 195 t stat in for these reasons and not try to worry about lower temps for no positive results.

Brian

[CMNTMXR57]

As mentioned though, unless you program the fans (at a minimum, the low speed fan), to come on at a lower temp to maintain and regulate the 180* (you could leave the high speed set at the factory 220* or whatever), in normal operation (such as stop and go trafffic), the car will still get to 195*, therefore catalyst light-off will still happen, and emissions will be fine.

Even at 180* it'll still be fine. You'll find most engines run at their optimum betweem 175* - 195*, so 180* is safe. It's when you get to 160* or cooler that the emissions become an issue.

With that said, I had a 180* in mine, and passed Illinois stringent OBDII test twice during my ownership, so... All I/M system monitors ran and passed too.

Heck, even chasing a P0420 this weekend (on a 3.8L car), where I commanded the PCM to run the readiness monitor, once of the first things I did was turn the high speed fan on (so it wouldn't come on automatically and possibly abort the test from the change in electric load that a fan kicking on would do), so that while running the diagnostic at 2,000 rpm for 5 minutes, the car ran at 174* and still kicked off and ran the catalyst test and passed. So 180* is fine. Put one in and enjoy.

[SLOGXP]

There is nothing to "enjoy" in putting a cooler thermostat in the car unless you like a motor that is not running as efficent as it should. Fans are to come on in stop and go traffic only. It does not matter what degree thermostat you run for fan control as their job is to keep the coolant cool when there is no air flow through the radiator. There is no benifit from running a cooler temp thermostat in a fuel injected, computer controlled car.

IE WEB REFERENCE:

Modern vehicles are programmed to work with a thermostat with a temperature rating for that automobile. Replacing it with one rated at a cooler temperature can cause issues with the fuel and spark control systems, resulting in poorer engine performance and fuel economy.

How Temperature Affects Engine Operation

Coolant temperature is used for a variety of engine and emission control functions. The coolant sensor on late model engines tells the computer when the engine has reached normal operating temperature. This, in turn, affects fuel enrichment, spark timing, operation of the EGR valve, purging of the charcoal canister, etc. Even on many non-computer engines, thermal vacuum switches (TVS) that react to a specific coolant temperature are used to open and close various vacuum circuits that regulate fuel enrichment, timing and emissions.

If a colder thermostat is installed, the coolant may never get hot enough to trigger the appropriate control functions in the computer or TVS vacuum circuits. As a result the engine will run as if it were continually cold, which increases both fuel consumption and emissions. Too low an operating temperature also increases cylinder wear.


Read more: What Are the Benefits of a Lower Temperature Thermostat? | eHow.com http://www.ehow.com/facts_7865940_benef ... z1neyCevaz

[CMNTMXR57]

There is nothing to "enjoy" in putting a cooler thermostat in the car unless you like a motor that is not running as efficent as it should. Fans are to come on in stop and go traffic only. It does not matter what degree thermostat you run for fan control as their job is to keep the coolant cool when there is no air flow through the radiator. There is no benifit from running a cooler temp thermostat in a fuel injected, computer controlled car.

IE WEB REFERENCE:

Modern vehicles are programmed to work with a thermostat with a temperature rating for that automobile. Replacing it with one rated at a cooler temperature can cause issues with the fuel and spark control systems, resulting in poorer engine performance and fuel economy.

How Temperature Affects Engine Operation

Coolant temperature is used for a variety of engine and emission control functions. The coolant sensor on late model engines tells the computer when the engine has reached normal operating temperature. This, in turn, affects fuel enrichment, spark timing, operation of the EGR valve, purging of the charcoal canister, etc. Even on many non-computer engines, thermal vacuum switches (TVS) that react to a specific coolant temperature are used to open and close various vacuum circuits that regulate fuel enrichment, timing and emissions.

If a colder thermostat is installed, the coolant may never get hot enough to trigger the appropriate control functions in the computer or TVS vacuum circuits. As a result the engine will run as if it were continually cold, which increases both fuel consumption and emissions. Too low an operating temperature also increases cylinder wear.


Read more: What Are the Benefits of a Lower Temperature Thermostat? | eHow.com http://www.ehow.com/facts_7865940_benef ... z1neyCevaz

Thanks for the education, I had NO idea about how thermostats and modern day PCM controlled vehicles work.

Either You completely missed (or didn't understand it), the first point I made in that it doesn't matter what temp thermostat you put in, if you don't reprogram the fans, in normal stop and go traffic you will reach the same temps you did with the stock thermostat in it. At which point you will meet all emissions requirements, You will be in closed loop operation, your HO2S's will be running their "Switch" rates and determining your STFT's and LTFT's to maintain stoich, your I/M system (usually the catalyst test, but sometimes the EGR test), will all run and pass. If it you get it in closed loop, the HO2S's are online and doing their job, and the PCM runs and passes all readiness monitors (the I/M system), then you're fine. A 180* t-stat in the LD8 will still do this.

The articles you linked and quoted above, are written with the perspective of the average automobile owner, which makes up 99.9% of the automotive population, who never opens the hood on his vehicle other than for oil changes or forced repair, and just wants the maximum reliability and efficiency from his/her automobile. Which there is nothing wrong with, and I concur, keep what is in there. There is no need for modification.

HOWEVER, if you are going for performance, this changes things. You can gain benefit from a cooler thermostat provided you can control your ECT's via fan (or vehicle movement). Lowering your ECT's also lowers your overall upper cylindrical engine temperatures, which in turn lowers combustion chamber temperatures. Lowering your combustion chamber temps allows you to tune your PCM with more aggressive fuel and spark mapping curves. More aggressive fuel and spark mapping curves mean more power. More power means better performance and better E.T.'s if you're tracking the car. If you're a forced induction engine, lowering the ECT's and combustion chamber temps is even more important and can provide even more benefit, especially if you're overdriving the supercharger. Many people at the track (Myself included), either turn the A/C system on while in the staging lanes (as it turns on the fans), or wire in a switch that can control the fans, in order to have them on, to maintain the 175* - 180* optimum ECT I want for maximum power from tune. You just have to remember to turn the A/C off as you stage.

As I said, I ran a 180* stat in my LD8, my car passed Illinois OBDII emissions testing, ran all I/M system monitors and passed (I think the LD8 has 7 to run and pass, I can look that up later), and had no ill-effects from it. No loss in fuel economy whatsoever. I actually seem to recall getting slightly better fuel economy.

But again, what do I know.

[SLOGXP]

Is there any reason why I shouldn't install a 180 deg stat in this thing? I know the normal temp range for a N* is 195-215 but I was wondering if there was any benefit to running a N* cooler?

Well your point is noted but we are not talking about racing here or highly modified computers and vehicles. The OP has a stock Northstar engine and was asking if there was a benifit to HIS car running a cooler thermostat. Ill stick with my original answer for him and say NO BENIFIT.

[CMNTMXR57]

Perhaps, but now he's Dp, has seen both points and can decide for himself which route to go.

[00Beast]

Honestly, for a Northstar, an engine known for killing cooling system components, even if it only runs 180* on the highway, that will prolong the life of any gaskets, especially in his climate where it can reach 100°+ in the summer-time.

Norm, I'd throw it in. It's not going to hurt anything.

[CMNTMXR57]

And freeze plugs...

[dpnewfie]

Considering I had given up on this almost 1 1/2 years ago and the t-stat is still sitting on a shelf in the garage. Further to this; considering the excellent advise I've gotten from a couple of the posters here ( ) I may just go ahead and give it a try. You know who you are!!!