170 degree thermostat???????

So i just called Napa today looking for a 180 degree thermostat for my 2007 5.7 and he couldnt pull anything up, however he could pull up a 180 degree thermostat for the 3.5 but the dimensions were way off....he did a little more looking in his system and found a 170 degree thermostat with the proper dimensions and fitment for the 6.1/5.7...anyone know if this is a good choice?

I only see ppl talking about the 180 so i'm curious if the 170 will gimme the same result or if anyone knows or has used it or run into problems

any help will be great as they only have one and i'll be going to get it in a few hrs

180, 170... doesnt make a huge difference... it only means your engine will run that much cooler... the thermostat is really just to tell the computer when to turn the cooling fans on and off...

So with my predator would i still just adjust my fans as if i was running the 180 degree? I've yet to see anyone post ne settings using a 170? any suggestions?

Here is some reading you might find interesting. I am not an expert on this subject so take it for what it is worth.....

Will installing a lower temperature thermostat help my engine run cooler and prevent it from overheating?


Yes, but it may cause more problems than it cures if you have a late model vehicle. Before emission controls and computerized engine controls came along, it was a common practice to install a cooler (160 to 180 degree F.) thermostat for summer driving. The lower thermostat lowered the engine's operating temperature, which in turn reduced the load on the cooling system and reduced the danger of overheating during hot weather driving or when towing a trailer.

It was also common practice to again replace the thermostat come fall and install one with a higher (190 to 195 degrees F.) temperature rating. This would raise the engine's operating temperature so the heater would put out more warm air on a cold winter morning.

This practice is no longer recommended because today's computerized engine control systems require a constant year-round operating temperature of about 195 degrees F.. The engine's emission controls as well as it's fuel and spark control systems are all calibrated to work within a given temperature range. If someone replaced the thermostat with the wrong one for the application (either colder or hotter), it can cause driveability, fuel economy, performance and emissions problems. So if the thermostat is replaced for any reason, it must be replaced with one that has the same (or correct) temperature rating for your vehicle.

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.

CAUTION: Under no circumstances should an engine be driven without a thermostat! This can produce thermal stress that may crack a head or block!

What about a hotter thermostat? A hotter than normal thermostat in a late model computer controlled engine may activate some control functions too quickly or out of sequence with other control devices (timer delays, etc.) --which could also have an adverse effect on driveability, fuel economy, performance and emissions.

The thermostat does not tell the cooling fans to turn on and off... the thermostat is there to allow coolant to flow though the radiator at a specified temperature thus allowing it to cool down and return into the engine. if the thermostat would tell the cooling fans when to turn on and off there would be no need to adjust the fans via tuner when changing out thermostats...which brings me to my next point if you don't have a tuner there is no reason to change out the thermostat as you need to calibrate the fans to work w/ the thermostat otherwise doesn't make sense to change.

I run a 170* as because i have a blower on my car.. prior to no need for a 170*... 180* was plenty cool...running a 170* will trigger check engine lights more frequently then a 180* thermostat will...even w/ a 180* depending on how you drive you will still get check engine lights.. the reason for the engine lights is the thermostat doesn't allow the vehicle to get up to normal operating temperatures in a timely manner hence is based off of how you drive.

In "Modify Tune"

Go to "Cooling Fans AC Off" Parameter.

Below are the settings for each parameter, depending on the Tstat you have.
Fan Speed - 170* Setting / 180* Setting

High MPH HS Fan On - 184.xx / 195.xx

LS - 166.xx / 178.xx

MS - 175.xx / 185.xx

Low MPH HS Fan - 184.xx / 195.xx

LS - 166.xx / 178.xx

MS - 184.xx / 195.xx

Once done with the above, exit back to the list of parameters you want to modify and go down one line to....

Go to the "Cooling Fans AC On" Parameter.

Below are the settings for each parameter depending on the Tstat you have.
Fan Speed - 170* Setting / 180* Setting

HS Fan On - 184.xx / 195.xx

LS - 166.xx / 178.xx

MS - 184.xx / 195.xx


Exit out and install tune.

Thanks irish! i'm gonna install this tomorrow seeing as how i got a bit of driving left to do today.

Silly question but being as i only have the predator tune and a CAI on mine even tho i have the 170* should i use the parameter's for the 170 or the 180?

What's the part number? Will help others out who want to go pick one up.

I picked mine up from my local Napa Parts Store

I believe its just Napa's brand 170 degree thermostat part # 65 it was $17.69 with tax

No Problem... you would still want to use the parameters for the 170... IMO if you install the 170 wait till spring its getting cool enough that you really don't need the 170 unless you race the car often... will cause you more of a headache clearing the cel... if you do decide to install then drive the car in stick mode to get up to temp quicker and then drive in auto esp on cold mornings..

Well leave it up to me to be impatient....of course i ran out and we took my gf's car to do the running so mine had a chance to cool and i installed and retuned with the 170* parameters i'm at the track quite a bit and i have somewhat of a lead foot neways so everyday is a track day when i see open road and a break in traffic haha!

on a sidenote i noticed one of those breather filters when i was at autozone getting coolant and wondered if there was any benefit to throwing one on the crankcase with the oddball dual intake i have set up i'd need 2 one for the crankcase and another just to seal off where that vaccum line ran into my intake but i was just curious if there was any benefit or if it was purely esthetic?

i have mine as a breather off of the intake manifold it is a good idea as it releases pressure w/ in the manifold however do you have an egr or is it deleted? the reason i ask is if you still have and is enabled you might get blow back in your engine bay from oil so be careful when doing this as far as having two one on the intake tube and one on the manifold area i wouldn't bother doing it at that point... remember where that one comes off on the intake tube you would be getting more heat from the engine bay coming into the air intake tube.. as it is directed right about the exhaust manifold then and id be willing to bet that you still have your splash shield on under the engine so you are storing heat.. leave it be for now in the future just get an intake that doesnt have one w/ the tube coming off of the intake or you can plug it but will look silly

yea i was thinking about the hot air i'd be pulling in as well, i think i might just see if i can figure out a way to plug it without it looking as if i have something off FRANKENSTEIN attached to my throttle body

The crank case breather hose just vents all of that shit into your air filter and it ain't cool fumes either. I use a 1/2 in. K&N breather filter instead. I don't have an air filter either. I have 3/8ths. in. screen on my head unit, lol.