Why the 160 degree thermostat?

[1JEWLDSSRS]

Totally absolutely awesome info Andrew!!! Thanks for sharing. I really needed to see all this to ease my mind when it gets over 100 out here in Florida, and I watch my coolant temps go up some, now I know I'm ok...

[el ess A]

You may be overthinking this using apples and oranges comparisons. Trust me, my understanding of how a cooling system works is not "flawed". You keep discussing modifications when I keep discussing stock setups. So I think we're talking past each other here. Once the thermostat opens fully, it's done its one and only job. If you have enough capacity to cool it to below the closing setpoint 50 times during a drive, great. But what if you don't have the capacity? So, it goes right back to what I said before. The thermostat doesn't care if you have capacity or not, it's going to open at whatever setpoint it's going to open, and if you don't have the capacity, it's staying open if the capacity and air flow can't bring your temps back down to below the t-stat setpoint. Simple as that. It's out of the equation once it's fully open. This is an irrefutable fact of life.

If you have the capacity and it's cold enough, it's back in the equation because now your system temps are closing it. But it doesn't do a darn thing for you as far as controlling anything other than minimum floor temp. Once it's fully open, it is no longer part of the operation. It's simply open like a door and now just another restriction in the fluid flow. Then it's up to the rest of the system to do it's job. If it's efficient, then it will make the thermostat do exactly what it did before. It'll drop below setpoint, the thermostat does the only thing it can do and start to close. It will stay closed until reaching the opening setpoint again. It doesn't do anything else.

It is not a temperature regulator, even though the end effect may seem like it. But then, is it worth the extra wear on the engine if you're running below 175 often? Perhaps, if you plan on running it hard and have the power and cooling capacity available to do so. But all this won't sway my thinking that a stock engine and setup has no need for a 160 thermostat. Yet that's one of the first things people tend to run out and do because it's inexpensive and sort of easy to do.

As you said, you have extra capacity to play with when dealing with power adders and other modifications so it may make sense to alter setpoints of fans, t-stats, and all that. When you start discussing modifications to the system, like manual fans, etc., you're changing the equations anyway. So all that other stuff goes out the window. But here again, manually operating the fans means proper air flow is crucial regardless of system.

You seem as if I'm against the 160 thermostat because I don't understand it. I do understand it. I'm not against using one if your setup can benefit from it. I know there may be applications where you would want to use it. But I still find those adding a 160 t-stat and CAI right out of the gate without doing anything else to a factory engine is probably not the best use of mod money, IMO. Unless you just like adding more wear a little at a time.

Compensations are made for the new and different equipment as you mod. High horsepower cars that are pushed with having the capacity to handle the extra heat load is good. Which is totally fine. Because that's what you're supposed to do when modding. Make sure everything else works to support the extra HP you're installing.

[acammer]

Originally Posted by el ess A

You may be overthinking this using apples and oranges comparisons. Trust me, my understanding of how a cooling system works is not "flawed". You keep discussing modifications when I keep discussing stock setups. So I think we're talking past each other here. Once the thermostat opens fully, it's done its one and only job. If you have enough capacity to cool it to below the closing setpoint 50 times during a drive, great. But what if you don't have the capacity? So, it goes right back to what I said before. The thermostat doesn't care if you have capacity or not, it's going to open at whatever setpoint it's going to open, and if you don't have the capacity, it's staying open if the capacity and air flow can't bring your temps back down to below the t-stat setpoint. Simple as that. It's out of the equation once it's fully open. This is an irrefutable fact of life.

If you have the capacity and it's cold enough, it's back in the equation because now your system temps are closing it. But it doesn't do a darn thing for you as far as controlling anything other than minimum floor temp. Once it's fully open, it is no longer part of the operation. It's simply open like a door and now just another restriction in the fluid flow. Then it's up to the rest of the system to do it's job. If it's efficient, then it will make the thermostat do exactly what it did before. It'll drop below setpoint, the thermostat does the only thing it can do and start to close. It will stay closed until reaching the opening setpoint again. It doesn't do anything else.

It is not a temperature regulator...

I agree, I think we're talking past each other a little bit. I'm trying to hear you. I appreciate that your baseline for how the system operates is related specifically to stock vehicles with stock thermostats, and I agree that modifications to thermostats, fan tuning, radiator size, etc all would have the potential to change how things function. Lets confine the discussion to the stock components until we reach agreement on how that works.

I highlighted the section(s) where we disagree. You suggest that the thermostat has a singular job of restricting flow to the radiator until normal operating temperature is reached, and then it's done, has no other function, and is "out of the equation". That's incorrect. The rest of your explanation goes on to contradict that your first point. You go on to say that the thermostat does have a second function of restricting coolant flow to the radiator temperature when the coolant becomes too cool.

You refer to the thermostat as a door - which implies either open or closed. That's a faulty explanation. The thermostat acts as a valve that controls flow, based on temperature. It can be closed, open just a little, open quite a bit, fully open, and anything in between. Under constant cruising conditions where the coolant would otherwise become too cool, the thermostat is operating in a partially closed position, regulating flow to the radiator to maintain a fairly tight temperature operating range.

You say the thermostat is not a regulator, but I'm not sure how you can see it as anything other than that. It is responsible for controlling coolant flow with the purpose of regulating the minimum coolant temperature. The cooling system (in a stock vehicle) has ample capacity to bring the coolant well below the normal operating temperature. The thermostat is responsible for getting the engine up to normal operating temperature quickly and keeping it at/above that point.

If we can't agree that a thermostat is in-fact a regulator (which is exactly what you describe while saying it's not) then I'm not sure how meaningful the rest of the conversation can be, as it all hinges on what the thermostat actually does.

[acammer]

Originally Posted by el ess A

...
But then, is it worth the extra wear on the engine if you're running below 175 often? Perhaps, if you plan on running it hard and have the power and cooling capacity available to do so. But all this won't sway my thinking that a stock engine and setup has no need for a 160 thermostat. Yet that's one of the first things people tend to run out and do because it's inexpensive and sort of easy to do.

As you said, you have extra capacity to play with when dealing with power adders and other modifications so it may make sense to alter setpoints of fans, t-stats, and all that. When you start discussing modifications to the system, like manual fans, etc., you're changing the equations anyway. So all that other stuff goes out the window. But here again, manually operating the fans means proper air flow is crucial regardless of system.

You seem as if I'm against the 160 thermostat because I don't understand it. I do understand it. I'm not against using one if your setup can benefit from it. I know there may be applications where you would want to use it. But I still find those adding a 160 t-stat and CAI right out of the gate without doing anything else to a factory engine is probably not the best use of mod money, IMO. Unless you just like adding more wear a little at a time.

Compensations are made for the new and different equipment as you mod. High horsepower cars that are pushed with having the capacity to handle the extra heat load is good. Which is totally fine. Because that's what you're supposed to do when modding. Make sure everything else works to support the extra HP you're installing.

This part we're pretty well aligned on. You ask a good question, is it worth the extra wear? That's a tough question to answer. First, how do we quantify how much extra wear? I mentioned before I studied this at length before, and concluded that 175*F operating temp is "about" the point where extra wear from cool temps becomes moot. The chart below is not mine and I do not know the specifics of the testing done to develop the data, but it pretty accurate summarized my position on temp vs. wear. For me, I want to see temps in the 180*F or better to feel good about not dramatically shortening the life of components.

I also agree that it's a common "early" mod because it's cheap and easy to do. Does it have any value on a stock-ish car? I think the answer there is yes, but limited. Consider that the OEM spark advance vs. coolant temp modifier start pulling timing at 195*F coolant temp - there is a gain to be had by operating below that point even in an otherwise complete stock configuration. Also consider the conservative nature of the OEM main advance table. That's one of the easiest places we pick up power with tuning, even with a stock vehicle, and keeping the engine cool to better tolerate additional timing is important to allowing a more substantial gain there.

As you said the OEM operating principals for the cooling system are out the window once we start modifying a vehicle for performance. Cooler operating temps give us the ability to improve performance and a better thermal margin to operate within.

I don't see you as against a lower temp thermostat, only against doing that on a car with minimal to no other mods. I'd agree with that if you're not to the point where your altering the OEM tuning calibration, a thermostat isn't worth much of anything, and the added wear (even if it's a miniscule amount) is unnecessary. If you're going to get into the tune (even on a car with minimal modifications) then a cooler thermostat open the door to other tuning changes with a positive effect on performance.

[el ess A]

I think it's safe to say we both have valid points, they're just approached from different avenues.

Nice graph depicting wear vs temps. It does point out though if you're living too far down the cold zone, you are more apt to increase engine wear. It may not show up as an issue for some time, but it's still happening. Like clogging arteries. A little everyday will eventually show up down the road. If you keep your car just a few years, then it probably won't ever be your problem. But if you're like me and keep a car 15+ years...

We also need to keep in mind that GM put a lot of fudge factor into the mix because they want to cover a lot of bases for the average motoring public. Many of us tune our cars to specific setpoints to extract as much benefit out of the entire package, whatever that may be.

Plus the fact that elevated (stock) normal op temperatures ensure the exhaust temps are hot enough to ensure the cats do their job to reduce the tailpipe emissions. Lower t-stats COULD, not saying they will, alter those tailpipe emissions negatively. So if you live in one of "those" areas where emissions are checked, you kinda don't want to do anything to potentially fail that test.

So I'm still going to maintain you should resist the urge to indescriminately pop in a 160 t-stat in your bone stock ride right away. If you've got a mod plan and it calls for it, then by all means, buy it and put it on the shelf with the rest of the parts that will compliment each other and do a once down, once up deal, tune it, and put the pedal down and have some fun.

[acammer]

Originally Posted by el ess A

I think it's safe to say we both have valid points, they're just approached from different avenues.

Nice graph depicting wear vs temps. It does point out though if you're living too far down the cold zone, you are more apt to increase engine wear. It may not show up as an issue for some time, but it's still happening. Like clogging arteries. A little everyday will eventually show up down the road. If you keep your car just a few years, then it probably won't ever be your problem. But if you're like me and keep a car 15+ years...

We also need to keep in mind that GM put a lot of fudge factor into the mix because they want to cover a lot of bases for the average motoring public. Many of us tune our cars to specific setpoints to extract as much benefit out of the entire package, whatever that may be.

Plus the fact that elevated (stock) normal op temperatures ensure the exhaust temps are hot enough to ensure the cats do their job to reduce the tailpipe emissions. Lower t-stats COULD, not saying they will, alter those tailpipe emissions negatively. So if you live in one of "those" areas where emissions are checked, you kinda don't want to do anything to potentially fail that test.

So I'm still going to maintain you should resist the urge to indescriminately pop in a 160 t-stat in your bone stock ride right away. If you've got a mod plan and it calls for it, then by all means, buy it and put it on the shelf with the rest of the parts that will compliment each other and do a once down, once up deal, tune it, and put the pedal down and have some fun.

I can't take credit for the graph, I found that somewhere in my researching years ago - but it illustrates your point that at some point on the temperature vs. wear curve, you're doing significant wear to an engine by running it too cold. The OEMs would land very far on the conservative side there, so from my perspective we can spare the 20*F of operating temperature in the name of performance without dramatically sacrificing long term wear.

No doubt you hit the nail on the head - the OEM engine tuning is ALL about emissions, and the cooling system operating temperature is very much a part of that. No doubt that a cooler thermostat will raise emissions. I don't know that it would pull things far enough to throw a sniffer, but it's a valid consideration.

I like your conclusion, and I agree: the 160*F thermostat mod, just like any mod, should be considered with the rest of the modifications, how you use the vehicle, and be complimentary. I think most of the time, in a performance use application, it makes all the sense in the world to make the change, but there could be cases where it doesn't.

I really like that we were able to debate a point we didn't share the same starting belief, and still stand with some differing perspectives, but were able to debate those perspectives respectfully without any sort of name calling. I hope that's a lesson for the forum, this is how you keep a disagreement classy! I appreciate the conversation.

[Leo72793]

Originally Posted by acammer

I can't take credit for the graph, I found that somewhere in my researching years ago - but it illustrates your point that at some point on the temperature vs. wear curve, you're doing significant wear to an engine by running it too cold. The OEMs would land very far on the conservative side there, so from my perspective we can spare the 20*F of operating temperature in the name of performance without dramatically sacrificing long term wear.

No doubt you hit the nail on the head - the OEM engine tuning is ALL about emissions, and the cooling system operating temperature is very much a part of that. No doubt that a cooler thermostat will raise emissions. I don't know that it would pull things far enough to throw a sniffer, but it's a valid consideration.

I like your conclusion, and I agree: the 160*F thermostat mod, just like any mod, should be considered with the rest of the modifications, how you use the vehicle, and be complimentary. I think most of the time, in a performance use application, it makes all the sense in the world to make the change, but there could be cases where it doesn't.

I really like that we were able to debate a point we didn't share the same starting belief, and still stand with some differing perspectives, but were able to debate those perspectives respectfully without any sort of name calling. I hope that's a lesson for the forum, this is how you keep a disagreement classy! I appreciate the conversation.

Wwith all that being said, For a fbo car thats driven daily in florida, spiritedly driven on the highway and mix of 60 city 40 highway, what would you use? Im still on the stock one from 2011. Currently my temps never see under 199-203°F even on the highway and city stays around 213-217°F.

GPI cam, 3400-3600 stall circle D triple disk, 3.45 rear gears, cai, headers, zl1 exhaust etc.

[el ess A]

Originally Posted by acammer

...

I really like that we were able to debate a point we didn't share the same starting belief, and still stand with some differing perspectives, but were able to debate those perspectives respectfully without any sort of name calling. I hope that's a lesson for the forum, this is how you keep a disagreement classy! I appreciate the conversation.

I appreciated it, too. I know people are going to do what they're going to do. I can't spend everyone's money for them. Everyone has their own opinions and there are normally at least 4 roads to the same destination.

I think we all should be thankful that GM actually gave us a great platform to start with so you can mod or not based on your own goals/desires.

[acammer]

Originally Posted by Leo72793

Wwith all that being said, For a fbo car thats driven daily in florida, spiritedly driven on the highway and mix of 60 city 40 highway, what would you use? Im still on the stock one from 2011. Currently my temps never see under 199-203°F even on the highway and city stays around 213-217°F.

GPI cam, 3400-3600 stall circle D triple disk, 3.45 rear gears, cai, headers, zl1 exhaust etc.

That's a clear case for a 160*F thermostat to me. You've got a setup that will generate significantly more heat, you like spirited driving, and you live in a hot environment. The lower stat will drop your cruising temps about 20*F, and with proper fan tuning should keep things under the 210*F mark even in the city.

[1JEWLDSSRS]

Originally Posted by Leo72793

Wwith all that being said, For a fbo car thats driven daily in florida, spiritedly driven on the highway and mix of 60 city 40 highway, what would you use? Im still on the stock one from 2011. Currently my temps never see under 199-203°F even on the highway and city stays around 213-217°F.

GPI cam, 3400-3600 stall circle D triple disk, 3.45 rear gears, cai, headers, zl1 exhaust etc.

I have pretty much the same set up, except I run a 4500 stall, TSP stage 3 cam, and I run the 160* Summit stat like acammer does, and all good, and I drive about the same as you do..

[Leo72793]

Originally Posted by acammer

That's a clear case for a 160*F thermostat to me. You've got a setup that will generate significantly more heat, you like spirited driving, and you live in a hot environment. The lower stat will drop your cruising temps about 20*F, and with proper fan tuning should keep things under the 210*F mark even in the city.

Originally Posted by 1JEWLDSSRS

I have pretty much the same set up, except I run a 4500 stall, TSP stage 3 cam, and I run the 160* Summit stat like acammer does, and all good, and I drive about the same as you do..

Late reply (camaro5 notifications arent working with gmail).

Found a pin that melted on my radiator fan assembly, causing primary fan to never come on. Warrantied it out under napa lifetime warranty. Ill be seeing how it behaves now. Idling at operating temp, i was at 187-189 with my AC on (both fans running). I may end up doing a 160 but we shall see what happens.

[Solders18]

Originally Posted by Leo72793

Late reply (camaro5 notifications arent working with gmail).

Found a pin that melted on my radiator fan assembly, causing primary fan to never come on. Warrantied it out under napa lifetime warranty. Ill be seeing how it behaves now. Idling at operating temp, i was at 187-189 with my AC on (both fans running). I may end up doing a 160 but we shall see what happens.

That'll happen on these big jobs

[acammer]

Originally Posted by Leo72793

Late reply (camaro5 notifications arent working with gmail).

Found a pin that melted on my radiator fan assembly, causing primary fan to never come on. Warrantied it out under napa lifetime warranty. Ill be seeing how it behaves now. Idling at operating temp, i was at 187-189 with my AC on (both fans running). I may end up doing a 160 but we shall see what happens.

Good catch. High heat and long run times will do it! Or sub-quality non-OEM stuff.

Originally Posted by Solders18

That'll happen on these big jobs

LOL, ain't that the truth!

[CamaroCracka]

Originally Posted by Leo72793

Found a pin that melted on my radiator fan assembly, causing primary fan to never come on. Warrantied it out under napa lifetime warranty. Ill be seeing how it behaves now. Idling at operating temp, i was at 187-189 with my AC on (both fans running). I may end up doing a 160 but we shall see what happens.

Found the same thing on mine a couple years back and replaced them with Weatherpack since I could not find that connector. 12ga Weatherpack connector has not melted, but one of the little plastic sleeves inside broke off inside, probably due to heat. It still works, but eventually I'll replace with better connectors.

I also run a 160 stat with the fans adjusted in the tune. I run about 30% ethylene glycol with a bottle of Super Cool and it stays between 180-190. During the winter it can drop into the 170s and on the hottest days it can touch 200.