Thermostat snake oil?

[Carl81]

Hi, I have the 160 degree in my car and although I can't see any real advantage, I use it anyway MAYBE to help me not over heat as quickly in bumper to bumper traffic on I-4. I want the fan on as early as possible. I also ran it without a thermostat at all most of one year, but you'll have almost no heat or a defroster for our 30 days of winter. That's not fun. My oil temperature stays about the same or less than the temp as the engine. I don't know if that is normal or not. Except in heavy traffic, it never over heats and seems to run well with the 160 degree temperatures.







www.mycarframes.com

[Rich Z]

Man, it's interesting all the anecdotal accounts we are getting about this issue.

[buckeyejack]

Guy's, Just putting in my 2 cents.
I believe a stock motor should run the 187* thermostat.( opening at 187* & closing at around 205*). That allows the engine intake to warm up enough the vaporize the fuel so that it burns completely in the combustion chambers.

Those engine w/ mods should use a thermostat of 180*, (still closing at around 200*). By adjusting when the cooling fan comes on, you can cool a HIGH HORSEPOWER motor effectively. The thermostat will open and close a lot more often.

With today's fuel (cheap stuff even at high octane), the warmer temp you run it , the better the fuel burns, there for better gas mileage.
And what's going to happen when they ( oil companys') start mixing in Ethanol in the near future. You'll have to run engines hotter to vaporize that fuel, since Ethanol will not vaporize fully at 180*. Lost horsepower and bad mileage. The cooler the intake air, the better the atoms of the fuel vaporize.
I had a big block Trans Am (76) that ran at 212* all the time. That motor was a screamer. Only changes to cooling system was the replacement of the fan blade. Used a 7 Blade fan off a Ford Crown Vic.

[exile]

OK, now I'm really confused ................. ...................

[Black C5]

OK, now I'm really confused ................. ...................:hide


Why?

[Rich Z]

Originally Posted by Black C5

OK, now I'm really confused ................. ...................:hide


Why?

Probably for the same reason I am....

I believe a stock motor should run the 187* thermostat.( opening at 187* & closing at around 205*).

Why in the world would a thermostat CLOSE at 205 degrees? In other words, as the engine heats up, the thermostat closes off the coolant flow. All that would do is to make the engine even HOTTER! I could see the thermostat closing at a much LOWER temperature, but higher? Either I am missing something really basic or there is an error in that post.

[buckeyejack]

Sorry guy's, I stand corrected by my brother-in -law.
The 180* thermo closes at 190*-195*.

The reason the thermostat closes at that temp. is to allow the hot coolant to stay in the radiator, so the air moving through the radiator can cool it back down before the thermo opens back up and sucks it in again. Therefore, the hot coolant( that is in the motor) is pushed through the motor to the radiator to be cooled in the same fashion as the gallon or so fluid before it. This is a continuing process. By having the fan come on earlier and pulling more air through, the coolant temp drops faster, making the motor run even cooler, especially in stop and go traffic.

Years ago the corvettes had 4 core radiators in them, made of copper. They could hold almost 4 gallons of coolant. And copper transfered heat very well.
But weight was a concern and copper is costly. Today's price is $30.68 a linear foot for copper, making that same radiator cost around $1000.00. So GM now uses alumium, which is lighter and cheaper to produce, but does'nt transfer heat as well. therefore you have to have a fan to pull fresh air through to cool it at the same rate copper did.

If you run a motor with-out a thermostat, that coolant does'nt stay in the radiator long enuff to cool down like it should. As long as you are moving, it my be ok, but as soon as your in stop and go traffic( with the sun baking the asphalt hot enuff to fry an egg) you have no air moving through the radiator to cool. So watch your temp gauge go up and the life of your motor go down.

Hope this helps those confused. - Boyd

[exile]

Originally Posted by buckeyejack

Sorry guy's, I stand corrected by my brother-in -law.
The 180* thermo closes at 190*-195*.

The reason the thermostat closes at that temp. is to allow the hot coolant to stay in the radiator, so the air moving through the radiator can cool it back down before the thermo opens back up and sucks it in again. Therefore, the hot coolant( that is in the motor) is pushed through the motor to the radiator to be cooled in the same fashion as the gallon or so fluid before it. This is a continuing process. By having the fan come on earlier and pulling more air through, the coolant temp drops faster, making the motor run even cooler, especially in stop and go traffic.

Years ago the corvettes had 4 core radiators in them, made of copper. They could hold almost 4 gallons of coolant. And copper transfered heat very well.
But weight was a concern and copper is costly. Today's price is $30.68 a linear foot for copper, making that same radiator cost around $1000.00. So GM now uses alumium, which is lighter and cheaper to produce, but does'nt transfer heat as well. therefore you have to have a fan to pull fresh air through to cool it at the same rate copper did.

If you run a motor with-out a thermostat, that coolant does'nt stay in the radiator long enuff to cool down like it should. As long as you are moving, it my be ok, but as soon as your in stop and go traffic( with the sun baking the asphalt hot enuff to fry an egg) you have no air moving through the radiator to cool. So watch your temp gauge go up and the life of your motor go down.

Hope this helps those confused. - Boyd

Sorry Boyd, I don't agree. This goes against everything I know about radiators, thermostats, and the way they work.

From "How Stuff Works":

Any liquid-cooled car engine has a small device called the thermostat that sits between the engine and the radiator. The thermostat in most cars is about 2 inches (5 cm) in diameter. Its job is to block the flow of coolant to the radiator until the engine has warmed up. When the engine is cold, no coolant flows through the engine. Once the engine reaches its operating temperature (generally about 200 degrees F, 95 degrees C), the thermostat opens. By letting the engine warm up as quickly as possible, the thermostat reduces engine wear, deposits and emissions.

If you ever have the chance to test one, a thermostat is an amazing thing to watch because what they do seems impossible. You can put one in a pot of boiling water on the stove. As it heats up, its valve opens about an inch, apparently by magic! If you'd like to try this yourself, go to a car parts store and buy one for a couple of bucks.

The secret of the thermostat lies in the small cylinder located on the engine-side of the device. This cylinder is filled with a wax that begins to melt at perhaps 180 degrees F (different thermostats open at different temperatures, but 180 F/82 C is a common temperature). A rod connected to the valve presses into this wax. When the wax melts, it expands significantly and pushes the rod out of the cylinder, opening the valve. If you have read How Thermometers Work and done the experiment with the bottle and the straw, you have seen the same process in action. The wax happens to expand a good bit more because it is changing from a solid to a liquid in addition to expanding from the heat.

This same technique is used in automatic openers for greenhouse vents and skylights. See this page for an example. In these devices, the wax melts at a lower temperature.

From "Wikipedia":

A thermostat is used in automobiles using an internal combustion engine to regulate the flow of coolant. When the thermostat is open, coolant passes through the cylinder head where it gets hot. It is then led from the engine into the radiator where it looses the heat to the air flowing through it. A “water pump” driven from the engine propels the coolant around the system. When the thermostat is closed the flow is prevented and so the engine is allowed to heat up to its optimum operating temperature.

This type of thermostat operates mechanically. It makes use of a wax pellet inside a sealed chamber. The wax is solid at low temperatures but as the engine heats up the wax melts and expands. The sealed chamber has an expansion provision that operates a rod which opens a valve when the operating temperature is exceeded. The operating temperature is fixed, but is determined by the specific composition of the wax, so thermostats of this type are available to maintain different temperatures, typically in the range of 70 to 90 °C (160 to 200 °F). Modern engines are run hot, that is, over 80 °C (180 °F), in order to run more efficiently and to reduce the emission of pollutants. Most thermostats have a small bypass hole to vent any gas that might get into the system (e.g., air introduced during coolant replacement). Modern cooling systems contain a relief valve in the form of a spring-loaded radiator pressure cap, with a tube leading to a partially filled expansion reservoir. Owing to the high temperature, the cooling system will become pressurized to a maximum set by the relief valve. The additional pressure increases the boiling point of the coolant above that which it would be at atmospheric pressure.

Don't mean to be disagreeable, but I couldn't let this one pass ........Tom

[Rich Z]

Yeah, this flies in the face of what I consider as reasonable as well. The thermostat is connected to the motor. If it CLOSED when the coolant temperature reached 190 to 195 degrees, since the thermostat is on the motor, regardless of what the temperature the coolant got in the radiator, the thermostat would be most affected by the temperature of the coolant in the motor itself. Yeah, heat can move by induction through a fluid, but which would have the most affect on the thermostat? The fluid remote in the radiator where the heat would have to travel the comparatively long path through the radiator hose where the fluid is NOT moving at all since the thermostat is closed, or the fluid in the motor right where the thermostat is located. So how cold would the fluid in the radiator have to get before it would be able to drop the temperature enough (at least below 180 degrees) for the thermostat to reopen?

Quite frankly, if the thermostat would close at 190 degrees or so in a running engine, the engine would quickly overheat, since the coolant temperature would NEVER fall back to 180 degrees again. At least not until after the engine self destructed.

But this could easily be tested. The boiling point of water is what, 212* F.? Simply put a thermostat in a pot of water. When the temp reached 180 degrees, it should open. If what is described about is true, as the boiling point of the water would approach, the thermostat will then close. Honestly, if that were to happen, I think my brain would leak out of my ears.

Again, this is not to start an argument but to understand the principles involved in how a thermostat works. Unless the thermostat is really two thermostats in one ((1)normally closed, opens on temperature rise, and also ((2)normally open, CLOSES at temperature rise), I can't see a single thermostat working in that manner.

[buckeyejack]

Originally Posted by Rich Z

Yeah, this flies in the face of what I consider as reasonable as well. The thermostat is connected to the motor. If it CLOSED when the coolant temperature reached 190 to 195 degrees, since the thermostat is on the motor, regardless of what the temperature the coolant got in the radiator, the thermostat would be most affected by the temperature of the coolant in the motor itself. Yeah, heat can move by induction through a fluid, but which would have the most affect on the thermostat? The fluid remote in the radiator where the heat would have to travel the comparatively long path through the radiator hose where the fluid is NOT moving at all since the thermostat is closed, or the fluid in the motor right where the thermostat is located. So how cold would the fluid in the radiator have to get before it would be able to drop the temperature enough (at least below 180 degrees) for the thermostat to reopen?

Quite frankly, if the thermostat would close at 190 degrees or so in a running engine, the engine would quickly overheat, since the coolant temperature would NEVER fall back to 180 degrees again. At least not until after the engine self destructed.

But this could easily be tested. The boiling point of water is what, 212* F.? Simply put a thermostat in a pot of water. When the temp reached 180 degrees, it should open. If what is described about is true, as the boiling point of the water would approach, the thermostat will then close. Honestly, if that were to happen, I think my brain would leak out of my ears.

Again, this is not to start an argument but to understand the principles involved in how a thermostat works. Unless the thermostat is really two thermostats in one ((1)normally closed, opens on temperature rise, and also ((2)normally open, CLOSES at temperature rise), I can't see a single thermostat working in that manner.

I believe i may have worded the post in a negative way. But after getting a shot of cooler water or coolant, does'nt the thermo start to close? Therefore regulating the flow? If not, I stand corrected and apologize for misleading anyone. - Boyd