Water Temperature
Burning Brakes
Joined: Feb 2004
Posts: 924
Likes: 2
From: Kearneysville West Virginia
I ran a 160 degree thermostat in my 1969 GTO for over 10 years. I ran the hell out of the car. Never had any problems. Finally sold it with 175,000 original miles on it. Engine had never been apart. Every time I changed oil or put new valve cover gaskets on, there were never any sludge problems. My experience is, that you can safely run a 160 degree thermostat with no problems.
Pro
Joined: Apr 2006
Posts: 625
Likes: 49
From: Southern California
sigh.....
supposed statement with no facts?
where are your facts?
here are some of mine:
From John Hinckley ( JohnZ here on CF), retired Chev. engineer and also currently Technical Writer for Corvette Enthusiast magazine and considered one of the foremost experts in the Corvette world.
Here is an article he wrote on the C2 / C3 cooling systems - BTW, this same article is also posted up on the DeWitts website because of it's accuracy:
http://lbfun.com/Corvette/Tech/vettetech.html
scroll down to the section called: ---cooling---
find article called:
cooling.pdf
by: John Hinckley
To save you the search and reading I copied the pertinent section and bolded the relative point:
"THERMOSTAT: Probably the most misunderstood component in the cooling system, the thermostat has absolutely nothing to do with controlling maximum engine operating temperature. Period. What does it do? At cold start, it blocks the flow of coolant out of the engine until the trapped coolant reaches the thermostat’s rated temperature, at which point it opens and permits coolant to begin circulating. This aids rapid warm up, which reduces cylinder bore and piston-ring wear by bringing the engine up to operating temperature relatively quickly. Once it’s open, it modulates the flow of coolant through its calibrated restriction so coolant temperature never drops below its rated opening point, assuming the cooling system is efficient enough to cool the engine down to that level. In most cars, it’s essentially wide open all the time, and only the heat transfer efficiency of the radiator and the airflow through the radiator determine the engine’s maximum operating temperature.
If you have a 180º thermostat and your engine operates at 220º, changing to a 160º thermostat won’t change your operating temperature one bit – you need more radiator, more airflow, or both, to reduce operating temperature. If you have an extremely efficient cooling system with more heat-rejection capability than your engine needs (runs at 180º with a 180º thermostat), changing to a 160º thermostat may result in reducing your operating temperature to 160º, but this is rare except in cold weather.
Furthermore, 160º is too cold; OEM testing has proven that the rate of cylinder bore and piston-ring wear at 160º is double the wear rate at 180º, and a coolant temperature of 160º won’t let the oil in the pan get hot enough to boil off condensed moisture and blow-by contaminants, which then remain in suspension and accelerate the formation of acidic sludge. 160º thermostats were specified in the 1930s for the old alcohol-based anti-freezes, which would boil off and evaporate at 185º; there’s no other reason for them. "
another experts opinion: This time from SWCDuke who use to hang in the C1/C2 forum. He is another GM engineer, specializing in Engine Systems Engineering.
http://forums.corvetteforum.com/show...ight=themostat
see his post # 4
A post from JohnZ again confirming the same thing: Assuming the cooling system has enough capacity to keep the temps fown to the t-stat rating (rare) running 160º is not good:
http://forums.corvetteforum.com/show...ight=themostat
see John's post # 16
more:
http://forums.corvetteforum.com/show...operating+temp
http://forums.corvetteforum.com/show...operating+temp
I could keep going on with more posts but honestly, i'm too tired of the entire subject now today.
I also see that before I posted this a link was posted to an article also stating the same thing John Hinkley is stating of the increased wear on the motor at lower operating temps. Thatr is just more confirmation of my point.
so.... hopefully you can see that lower operating temps are bad for a motor in the real world. Yes, you may actually gain some small increase of HP at the lower temp but at the expense of the motor by doing so.
Again, I agree 100% that in most cases even if you do run a 160º t-stat that chances are the motor is still going to run at operating temps above that so all of this becomes irelevant, but in cases where the cooling system has enough cooling capacity to keep the operating temps at the same level as the t-stat you are bringing on trouble because the operating temps are now too low.
bye
supposed statement with no facts?
where are your facts?
here are some of mine:
From John Hinckley ( JohnZ here on CF), retired Chev. engineer and also currently Technical Writer for Corvette Enthusiast magazine and considered one of the foremost experts in the Corvette world.
Here is an article he wrote on the C2 / C3 cooling systems - BTW, this same article is also posted up on the DeWitts website because of it's accuracy:
http://lbfun.com/Corvette/Tech/vettetech.html
scroll down to the section called: ---cooling---
find article called:
cooling.pdf
by: John Hinckley
To save you the search and reading I copied the pertinent section and bolded the relative point:
"THERMOSTAT: Probably the most misunderstood component in the cooling system, the thermostat has absolutely nothing to do with controlling maximum engine operating temperature. Period. What does it do? At cold start, it blocks the flow of coolant out of the engine until the trapped coolant reaches the thermostat’s rated temperature, at which point it opens and permits coolant to begin circulating. This aids rapid warm up, which reduces cylinder bore and piston-ring wear by bringing the engine up to operating temperature relatively quickly. Once it’s open, it modulates the flow of coolant through its calibrated restriction so coolant temperature never drops below its rated opening point, assuming the cooling system is efficient enough to cool the engine down to that level. In most cars, it’s essentially wide open all the time, and only the heat transfer efficiency of the radiator and the airflow through the radiator determine the engine’s maximum operating temperature.
If you have a 180º thermostat and your engine operates at 220º, changing to a 160º thermostat won’t change your operating temperature one bit – you need more radiator, more airflow, or both, to reduce operating temperature. If you have an extremely efficient cooling system with more heat-rejection capability than your engine needs (runs at 180º with a 180º thermostat), changing to a 160º thermostat may result in reducing your operating temperature to 160º, but this is rare except in cold weather.
Furthermore, 160º is too cold; OEM testing has proven that the rate of cylinder bore and piston-ring wear at 160º is double the wear rate at 180º, and a coolant temperature of 160º won’t let the oil in the pan get hot enough to boil off condensed moisture and blow-by contaminants, which then remain in suspension and accelerate the formation of acidic sludge. 160º thermostats were specified in the 1930s for the old alcohol-based anti-freezes, which would boil off and evaporate at 185º; there’s no other reason for them. "
another experts opinion: This time from SWCDuke who use to hang in the C1/C2 forum. He is another GM engineer, specializing in Engine Systems Engineering.
http://forums.corvetteforum.com/show...ight=themostat
see his post # 4
A post from JohnZ again confirming the same thing: Assuming the cooling system has enough capacity to keep the temps fown to the t-stat rating (rare) running 160º is not good:
http://forums.corvetteforum.com/show...ight=themostat
see John's post # 16
more:
http://forums.corvetteforum.com/show...operating+temp
http://forums.corvetteforum.com/show...operating+temp
I could keep going on with more posts but honestly, i'm too tired of the entire subject now today.
I also see that before I posted this a link was posted to an article also stating the same thing John Hinkley is stating of the increased wear on the motor at lower operating temps. Thatr is just more confirmation of my point.
so.... hopefully you can see that lower operating temps are bad for a motor in the real world. Yes, you may actually gain some small increase of HP at the lower temp but at the expense of the motor by doing so.
Again, I agree 100% that in most cases even if you do run a 160º t-stat that chances are the motor is still going to run at operating temps above that so all of this becomes irelevant, but in cases where the cooling system has enough cooling capacity to keep the operating temps at the same level as the t-stat you are bringing on trouble because the operating temps are now too low.
bye
Like I said before, if we are showing at least 212* oil temp, we are good to go for condensation boil-off and the prevention of acid or sludge formation. You can certanily see 212* oil temp while running a 160* thermostat, since in most cases it is simply open anyway. But yes you'd like to have a gauge to know for sure. So much for the oil temp issue.
As for the wear issue, all we ever get is vague references to OEM testing. OK fine, but what is the DATA? Exactly how many engines were tested for this? If it wasn't a fair number of them, then it brings into question just how valid that test really was. Were the engines precisely blueprinted in order to accurately see any difference? How much wear exactly was noted? How were the test engines actually run? How long in time and/or miles. What oil was used? How often was it changed? Etc, etc, etc. THIS is what I was referring to when I said data to back it up, not just more people making the same vague references. More people saying something doesn't make it any more correct.
Only the supporting data might make it believable. And I say "might" because we have any number of people saying it has never been an issue for them when they run a 160* thermostat. We know it can help prevent detonation. And we know it can make more power. In addition to that, I personally have never come across one single person who said they for a fact "did" have a problem with wear or anything else from doing it.
So, on the NO side, all we get is "the sky is falling". On the YES side, all we get is "no problem". Everyone obviously has to decide for themselves what seems right, and live with their choice.
Le Mans Master
Joined: Apr 2000
Posts: 5,202
Likes: 10
From: cincinnati ohio
St. Jude Donor '09
Like I said before, if we are showing at least 212* oil temp, we are good to go for condensation boil-off and the prevention of acid or sludge formation. You can certanily see 212* oil temp while running a 160* thermostat, since in most cases it is simply open anyway. But yes you'd like to have a gauge to know for sure. So much for the oil temp issue.
Former Vendor
Joined: Jan 2000
Posts: 5,593
Likes: 631
From: Brighton
I'm with BarryK on this one, 180 is prefered. Why? Because GM says so. GM installed 180's and thats good enough for me. Forget all the arguing who's right and/or why. GM wanted the engine to run at 180. I read though this thread and without quoting anyone in particular, some still do not understand the stat function and I'm not going to try to explain it. Been there, done that (x1000)
Edit: and if anyone he feels GM was wrong and 160 is better for some reason, (except for trying to fix an overheating problem) then go ahead an use it.
Edit: and if anyone he feels GM was wrong and 160 is better for some reason, (except for trying to fix an overheating problem) then go ahead an use it.
Last edited by Tom@Dewitt; Apr 11, 2007 at 09:12 PM.
Burning Brakes
Joined: Feb 2004
Posts: 924
Likes: 2
From: Kearneysville West Virginia
I'm with BarryK on this one, 180 is prefered. Why? Because GM says so. GM installed 180's and thats good enough for me. Forget all the arguing who's right and/or why. GM wanted the engine to run at 180. I read though this thread and without quoting anyone in particular, some still do not understand the stat function and I'm not going to try to explain it. Been there, done that (x1000)
Edit: and if anyone he feels GM was wrong and 160 is better for some reason, (except for trying to fix an overheating problem) then go ahead an use it.
Edit: and if anyone he feels GM was wrong and 160 is better for some reason, (except for trying to fix an overheating problem) then go ahead an use it.
The bottom line is, there seems to be no hard evidence against running a 160 degree thermostat. There is experience that suggests that the 160 degree stat will reduce pinging. There is experience that shows no significant oil related problems with the 160 degree stat. I have run both, and I can't say with any certainty that I see any negative effects except that the heater doesn't put out as much heat with the 160 degree stat.
For the production vehicle that any person might buy and drive every day in any conditions, I am certain GM reserached and tested and found that the 180 degree stat was optimum for all average driving conditons and emissions requirments. However, most of us like to fine tune our vehicles for our particular application, and part of that might be a cooler thermostat. My experience has shown, that if you want to run a 160 degree stat, go ahead, you are not going to hurt anything. If you want to run a 180 degree stat, do it because you want to or it works best for you, not because GM said so.
