You are absolutely correct, and its nice to see someone who "gets" it when it comes to cooling systems

But there are some who do NOT understand how a cooling system works at all, even though they think they are the only ones who do. To say a lower rated thermostat will cause an engine to overheat because the water isn't in the radiator long enough to cool, is totally laughable. And the folks who believe that are sadly unaware of reality. They need to do some serious reading and/or wrenching to get a clue as to what really goes on.

Of course, just as you suggested, the thermostat only determines the minumum temp that an engine runs. After that its the system's overall capacity that determines how warm it runs.

I've personally run 160* thermostats in hot Southern California year 'round for years and years, with no overheating issues at all, ever. I've never had sludge issues, nor any other issue with that either. And a number of gearhead buddies have done the same thing, also without issue. Letting the engine run at around 160*, assuming your setup is capable of keeping it that cool, helps prevent detonation on pump gas, and allows the engine to make more hp. I even have a couple of buddies who run NO thermostat, and do so, also without issue, they stay nice and cool. Anyone who has played with engine temps on a dyno or at a dragstrip, will tell you, the cooler it runs, the more hp it makes. This stuff is not Rocket Science.............

 

You remind me of my father-in-law. He's a damn know-it-all too.

I see you both are from southern california, explains alot, right there. BBTank

 

160 here for 6 years, two engines. No problems or sludge and I know for a fact my engine ran cooler after removing a 195.

 

Whats wrong with a 160??? never had a problem here aswell

 

180* is supposed to be the prime operating temp for minimal engine wear.

 

I have been running 160's since the 1970's in GTOs, Vettes, Stangs, you name it. I can tell you they make your old, clogged 2 row radiator new (4 row or better!). Seriously, I want my engines to come up to operating temp quickly. A 180* stat is probably fine. I guess I'm a little leary of anything higher, as big blocks generate a lotta heat.

 

Wow, we all have our own experience, how refreshing.

And it looks as it has all worked for us.

My big block seems happy at 185-200*, but that's just mine.

 

I have taken some thermodynamic classes and it is definitely true that you want the largest difference in temp between reservoirs(in this case ambient temp and engine temp) for max efficiency. The easiest way to do this is to increase the engine temp by getting a hotter thermostat. (Since you are going to have a hard time affecting the ambient temp). However, with a gasoline engine you have to consider detonation at higher temperatures.

Currently with my 160 it runs around 155-165 no problem. I guess the real question I want answered is how hot can I run a 9.6 compression aluminum head motor without detonation on 91 octane?

I am thinking 180 or 195 to be safe.

Also, I am pretty sure new cars run at 210+. Obviously I will not be able to get away with that much since this is not a new car, but it is worth noting.

 

Oh...that bit of misinformation has been around for a very long time. Some of the problems in thermodynamics classes for mechanical and civil engineering courses involves cooling systems, so any engineer that does their homework and studies the subject material like I did discovers that the faster the coolant flows through the system the faster the radiator removes heat. The same is true for the air flow...the faster air is made to pass through the radiator the faster the radiator removes heat.

I think it might be easier to understand when you consider that heat flows quicker when there is a large temperature difference between the coolant and radiator. You can test this by putting an ice cube in a metal pan and sit it out on the counter...it will take a long time to melt...perhaps even an hour. But, sit it in a 350º oven and it will melt away to nothing in under a minute due to the quicker heat flow from the temperature variance. If you let the coolant sit in the radiator then the difference between the coolant and radiator will decrease to a point where there will be no heat flow at all.

So, a thermostat restricts the coolant flow...which is why I remove my thermostat in the summer. Engines without a thermostat tend to run at around 160º anyway...so a 160º thermostat allows an engine to quickly reach it's ambient temperature, but might restrict the coolant flow enough to prevent it from removing heat fast enough to avoid over heating on very hot days when the A/C is running and in heavy traffic. A 195º thermostat is great for cold winters like this one...it not only allows the coolant temp to quickly reach normal levels, but also gets the coolant hot enough to have a nice toastie heater and defroster. I don't really see any use for a 180º T-stat unless you just don't like a toastie heater.

Thus, right now...in the middle of winter...the best T-Stat to install would be a 195º.

 

When I built my aluminum head, 9.6CR engine, I installed a 180° thermostat. The temp gauge reflected this lower temp at all times. About a year ago I installed a 195° thermostat, same as the car originally came with. The temp gauge now runs a little to the left of the 210 mark. I live in an area that often gets into triple digits in the summer. The car does not overheat. If I am stuck in stop and go traffic, the needle moves up the thickness of the needle, maybe two needles worth. As soon as I get on the open road, and get some air flowing, the temp gauge goes right back down to where it normally sits. I run 91 octane and it does not ping or show any signs of denotation. I have no plans to go back to the 180° stat.

I'm just reporting my experience, other opinions may vary!

 

Here's another misinformation for you I'm sure, Professor. In Southern AZ it gets to be 115 "ambient" temp. The roads are how hot then??? And that affects my engine by how many degrees?

I have a big block in this kinda temps too. Should I take my T-stat out when it reaches 100* and above?


Pray tell, professor rock n roll, what college class did you have to take to find out ice melts faster in a 350* oven than on your countertop at 75*. I learned that in the 3rd grade in redneck, backwards azz NC.

I invite you to find a big block C3 Corvette and come visit me in late July, early Aug. and we'll go cruise, and put all that high faluting knowledge of yours to the real world test. The hell with physics, books, and college classes. I know what I know, and it has worked for street cars, 8 sec. drag cars for over 30 years.


You got the answers, I got the questions, teach me something Professor, I'm just a dumb ole redneck.

 

All production cars come from the factory with a thermostat installed. Running without one does not make sense. If coolant does not flow suffieiently, you have a blockage, stuck 'stat or pump issue, not a good 'stat issue. For my 68 L36 in sunny CA, a 160* thermostat does the job.

 

I'm with you, but I want to hear the professor above with his college learnin teach me something

 

You can put a 100 degree thermostat in it, but it will probably run around a 180. Of course, it will probably run cooler in the winter, but we're usually concerned about the heat.
Larry

 

Sometimes we overthink issues. While it is true that a blockage will cause overheating, thermostats are designed to open sufficiently as to not cause blockage. That has nothing to do with thermodynamics. Or, a whole bunch of engineers were absent on that day... Just kidding; I enjoy reading all posts.

 

but the engine and radiator coolant dont cycle like that, they come to a steady state and the t-stat stays open.

 

perhaps you could consider chilling out for a second, taking a step back, and realizing that nobody is insulting you or your experience. there is enough elbow room in cooling system performance for both a 195 and a 160 to perform satisfactorily. nobody is insulting you, only insulting the myths that are perpetuated in our hobby.

 

Thanks for the concern, no kidding. It takes alot more than CF to get me steamed. I get steamed over life threating issues, not thermostats, and know-it-all people. Whether what I said is a myth or not, I think that the attitude some CF members use is, I know what I'm talking about, you're an idiot, shut up nOOb. I haardly think a retired Vet of 52 is a newbie. It's kind of a shame that some think they know all. I said it once, I know what I know, that's it.


The world doesn't revolve around this damn forum, and I've been around the world, twice. And I still got a limp to prove it, 14 years later.


I thought this is supposed to be fun, informative, and a place to talk to others that have the same interest, and it's even broken down into types of interest too.

My neighbor is an engineer, a real engineer, trained in college even, and he couldn't beleive what he read on this post. Let's face it, it's just a stupid question on a damn thermostat, let's take it to the moon and back, when the OP asked a simple question.

My invite for late July/early August still stands, bud


BBTank

 

Well we seem to be getting a little off topic out here.....

I started this thread to try to find some opinions about max water temp a motor (mine in particular) should be run. And Thermostat DOES have a lot to do with this. Your Thermostat sets your lowest operating temp. Your highest is determined by radiator, water pump, ambient temp, etc. If with a 160 thermostat the car runs at about 160 then increasing the temp the thermostat opens will adjust the operating temp accordingly.

Please don't argue about opinions and experience and start calling people out. That was not the purpose of this thread. I think you guys can find a different place to hang out if you want to act like 7 year olds.

Thank you to those of you that have left valuable feedback.

 

As I stated in a previous reply, I run 180 deg stat. I also run 10:1 compression with Alum heads and have no detonation issues which I forgot to mention.