# Whats the best temperature for the thermostat to be set on?



## nikedo420 (Nov 10, 2007)

I dont know if this is the right category. But I was wondering if i should change my thermostat temperature.. My friend changed his on his vette and made it a little cooler and it runs a bit smoother. Could the same be said for my 04 GTO? My fans kick on at 226.. is that normal? Could I get better performance by running it a little cooler???


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## Poncho Dan (Jun 30, 2009)

Leave the stock thermostat, tune the fans. Mine rarely goes above 197.


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## GM4life (Mar 18, 2007)

nikedo420 said:


> I dont know if this is the right category. But I was wondering if i should change my thermostat temperature.. My friend changed his on his vette and made it a little cooler and it runs a bit smoother. Could the same be said for my 04 GTO? My fans kick on at 226.. is that normal? Could I get better performance by running it a little cooler???


Yes, it reduces heat soak. To get full advantage of the cooler running thermostat is to lower the fan temps. Do a search we have covered this same subject before.


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## nikedo420 (Nov 10, 2007)

**

Cool thanks much


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## svede1212 (Nov 1, 2005)

I'd do what Dan said. Leave the stat and tune the fans. I've never seen any data that shows running the coolant a little lower does much of anything. If it did we'd be running 100* stats. It seems to be one of those "common knowledge" things that gets legs and runs


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## GM4life (Mar 18, 2007)

nikedo420 said:


> Cool thanks much


Your best bet it to get a 160 thermostat if you ever see a 170 don't bother the stock thermostat is 186. I ran the stock for along time until I started modding I was told by my tuner who has been doing this for along time to run the 160.


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## GM4life (Mar 18, 2007)

svede1212 said:


> Leave the stat and tune the fans. I've never seen any data that shows running the coolant a little lower does much of anything. If it did we'd be running 100* stats. It seems to be one of those "common knowledge" things that gets legs and runs


With that said. Why even bother to lower the fan temps?


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## svede1212 (Nov 1, 2005)

GM4life said:


> With that said. Why even bother to lower the fan temps?


Because of water's boiling point and high heat's effect on warp-age and such. Other than "common knowledge" like your tuner professed I've never seen any data on benefit in longevity or performance. In fact running an engine too cool can be detrimental in the long haul. Oddly enough they engineer them to run in a fairly narrow range for peak efficiency


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## GM4life (Mar 18, 2007)

svede1212 said:


> Because of water's boiling point and high heat's effect on warp-age and such. Other than "common knowledge" like your tuner professed I've never seen any data on benefit in longevity or performance. In fact running an engine too cool can be detrimental in the long haul. Oddly enough they engineer them to run in a fairly narrow range for peak efficiency


Waters boiling point is higher because of antifreeze and pressure. Stock is not even close to cause damage. I don't think its common knowlage. Tuners don't make money off of thermostats. Besides I trust my tuners knowlage over anyone elses he has been doing this for many years. I never seen any data supporting being bad for an engine, running ~15 or so below stock operating temp. The advertised range on a t-stat is where it starts to open. I haven't seen data that supports both are claims so I'm not agreeing or disagreeing with you.


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## Poncho Dan (Jun 30, 2009)

Tune the fans to be close to tstat temp, because, why have a 20-30+ degree temperature swing? Consistency is probably the best. Like I said, the wildest swings on mine are between 189-197, a whole 8 degrees.

BTW, if you want control of the fans below 192, you need to flash a custom operating system to the PCM.


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## GM4life (Mar 18, 2007)

That big of a gap is to let the car air cool first before the fans come on is my guess. My fans were lowered before I put in the 160 w/stock t-stat and they seem to run alot. With my 160 my operating temp is in the 180's not to much off from yours.


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