Redline Water Wetter and Royal Purple Purple Ice

[Kaboomba]

Good grief. I feel compelled to leave a succinct (Haw!) post that the masses can actually use.

1. The goal of the thermostat is to "turn on" the heat exchanger (radiator) to reject excess heat energy from the engine into the atmosphere. "excess" means that the continued operation of the engine will cause block and head temps to go too high.

2. The thermostat regulates coolant temperature (rejects "excess" heat energy) by regulating flow to the heat exchanger (radiator) as a function of coolant temperature. i.e. higher temperature coolant on top of the engine will correspond to higher flow rate through the thermostat, to a limit defined by the water pump performance.

3. A heat exchanger is so-called because if it is brought into contact with a fluid that is colder than itself, it will cool as the fluid warms. If there is no temperature difference between the heat exchanger and the fluid, no energy transfer (heat rejection) takes place. A car's radiator, heater core, oil cooler, engine block (including heads, IM), ATF cooler, are all heat exchangers.

4. When the thermostat opens, it lets hot coolant into the radiator. Now that the radiator is hotter than the air around it, it begins to reject heat into the air. Heat transfer occurs.

5. The rate of heat rejection increases as the temparature differential between the working fluids (in this case, coolant and air) increases. Always. But the resistance to the heat transfer varies, and can limit heat transfer rates. For instance, radiators are usually painted black because the emissivity of the black surface is higher than for a polished metal surface, and more heat energy can be transferred FOR A GIVEN TEMPERATURE DIFFERENTIAL.

6. Rate of heat transfer is limited by flow rates and specific heat capacities. A kilo of water will only gain so much heat energy for a given temperature change.

7. Surfactant products such as water wetter increase the real-life maximum cooling capacity of your car's cooling system by improving the efficiency of heat transfer (point 5, above) from the engine block to the coolant and from the coolant to the metal in the radiator.

Note: You can safely increase the cooling capacity of your car's cooling system by simply increasing the proportion of water in the system. For example, going from 50/50 to 70/30 water/propylene glycol will give your system ~15% more cooling capacity with NO other changes. This is becasue water has a higher specific heat capacity than propylene or ethylene glycol. Physics, baby. Beautiful.

Best

Kaboomba

 

[azsynthetic]

Originally Posted By: Kaboomba
Good grief. I feel compelled to leave a succinct (Haw!) post that the masses can actually use.

1. The goal of the thermostat is to "turn on" the heat exchanger (radiator) to reject excess heat energy from the engine into the atmosphere. "excess" means that the continued operation of the engine will cause block and head temps to go too high.

2. The thermostat regulates coolant temperature (rejects "excess" heat energy) by regulating flow to the heat exchanger (radiator) as a function of coolant temperature. i.e. higher temperature coolant on top of the engine will correspond to higher flow rate through the thermostat, to a limit defined by the water pump performance.

3. A heat exchanger is so-called because if it is brought into contact with a fluid that is colder than itself, it will cool as the fluid warms. If there is no temperature difference between the heat exchanger and the fluid, no energy transfer (heat rejection) takes place. A car's radiator, heater core, oil cooler, engine block (including heads, IM), ATF cooler, are all heat exchangers.

4. When the thermostat opens, it lets hot coolant into the radiator. Now that the radiator is hotter than the air around it, it begins to reject heat into the air. Heat transfer occurs.

5. The rate of heat rejection increases as the temparature differential between the working fluids (in this case, coolant and air) increases. Always. But the resistance to the heat transfer varies, and can limit heat transfer rates. For instance, radiators are usually painted black because the emissivity of the black surface is higher than for a polished metal surface, and more heat energy can be transferred FOR A GIVEN TEMPERATURE DIFFERENTIAL.

6. Rate of heat transfer is limited by flow rates and specific heat capacities. A kilo of water will only gain so much heat energy for a given temperature change.

7. Surfactant products such as water wetter increase the real-life maximum cooling capacity of your car's cooling system by improving the efficiency of heat transfer (point 5, above) from the engine block to the coolant and from the coolant to the metal in the radiator.

Note: You can safely increase the cooling capacity of your car's cooling system by simply increasing the proportion of water in the system. For example, going from 50/50 to 70/30 water/propylene glycol will give your system ~15% more cooling capacity with NO other changes. This is becasue water has a higher specific heat capacity than propylene or ethylene glycol. Physics, baby. Beautiful.

Best

Kaboomba



Oh man, I was having so much fun with the shade tree mechanicx and Dodge engine overhaulers on this board until you come around. Every body should read item 2 and notice that the thermostat does not regulate or control engine temperature.

Thank you to the man that can understand physics.

 

[mechanicx]

Several of us have been basically saying the same thing Kaboomba said all along, ie., that the cooling system and ambient temps determines heat transfer capacity. I don't know that he is agreeing with you, but I still say you are mish mashing things. an engine can overcool or even overheat without a t-stat. The cooling system is designed to flow at a rate of a fully open thermostat.

 

[Kaboomba]

The thermostat "controls" engine block temperature (effectively limits it until the system reaches a saturation point, i.e. maximum heat rejection capacity of the cooling system) by sensing temperature of the water jacket and "turning on" the heat exchanger (radiator) by allowing coolant to flow through.

K

 

[Shannow]

Yep, he's just got some personal (financial ? sells more products ? prestige?) issue that requires the laws of physics to work differently for vehicle thermostats and water wetter.

 

[lipadj46]

Regardless you guys are arguing over symantics. Believe me I'm mostly Polish and can pointessly argue for hours just because I'm stubborn but 4 pages arguing over the function of a thermostat is hardcore. Kudos to you.

 

[azsynthetic]

Originally Posted By: Kaboomba
The thermostat "controls" engine block temperature (effectively limits it until the system reaches a saturation point, i.e. maximum heat rejection capacity of the cooling system) by sensing temperature of the water jacket and "turning on" the heat exchanger (radiator) by allowing coolant to flow through.

K


At a system level there are many things that contribute to the engine block temperature. The two main one are frictional and combustion heat. The thermostat does not control the engine block temperature since it can not control frictional nor combustion heat. Its job is to try to maintain the engine temperature within a wide range (30-40 degrees). I said "try" because the engine can still overheat or never get up to temperature. The radiator is fully functioning 24/7 even with the engine turned off. The thermostat does not turn it on but merely control the coolant flowing through it. You can remove the thermostat and the radiator would not know the difference.

 

[azsynthetic]

Originally Posted By: lipadj46
Regardless you guys are arguing over symantics. Believe me I'm mostly Polish and can pointessly argue for hours just because I'm stubborn but 4 pages arguing over the function of a thermostat is hardcore. Kudos to you.


You might consider it semantics (not symantics) but when you are trying to write a patent or describe in detail the function of each components in a system then you have to be very precise and technical.

 

[Shannow]

Originally Posted By: azsynthetic
At a system level there are many things that contribute to the engine block temperature.


I thought that we were arguing coolant, temperature, and the control mechanism for THAT...which is the thermostat.

 

[440Magnum]

Originally Posted By: azsynthetic
Originally Posted By: Kaboomba

2. The thermostat regulates coolant temperature (rejects "excess" heat energy) by regulating flow to the heat exchanger (radiator) as a function of coolant temperature. i.e. higher temperature coolant on top of the engine will correspond to higher flow rate through the thermostat, to a limit defined by the water pump performance.


Oh man, I was having so much fun with the shade tree mechanicx and Dodge engine overhaulers on this board until you come around. Every body should read item 2 and notice that the thermostat does not regulate or control engine temperature.

Thank you to the man that can understand physics.


#2 says EXACTLY what everyone EXCEPT YOU has been saying on this thread for weeks now.

And if you somehow think that a centrifugal pump like a typical automotive water pump can reverse its flow direction simply because the thermostat is installed backwards, then you must live in a universe where conservation of momentum and centripetal acceleration don't function like they do in this universe.

 

[mechanicx]

Well I guess a backwards installed thermostat that isn't opening will likely eventually reverse coolant flow. It's called overheating and boiling over

. But even though a working thermostat would've prevented overheating it still doesn't control coolant temperature! (/sarcasm)

Of course if the backwards t-stat should crack open due to a combination of pressure differential or heat conducting to the pellet, coolant is going to flow out, not in or backwards.

 

[440Magnum]

Originally Posted By: mechanicx
Well I guess a backwards installed thermostat that isn't opening will likely eventually reverse coolant flow. It's called overheating and boiling over

. But even though a working thermostat would've prevented overheating it still doesn't control coolant temperature! (/sarcasm)

Of course if the backwards t-stat should crack open due to a combination of pressure differential or heat conducting to the pellet, coolant is going to flow out, not in or backwards.


You're right- if enough heat leaks past the backward thermostat, it will probably open. But its an unstable system- if the engine load goes way down and the ambient temperature is low enough to cause the thermostat to close again, it loses its control "signal" and won't re-open until the engine is at or near overheating again.

But under NO circumstances would it initiate reverse flow through the waterpump and cooling system like he suggested earlier.

 

[Kaboomba]

Originally Posted By: azsynthetic

At a system level there are many things that contribute to the engine block temperature. The two main one are frictional and combustion heat. The thermostat does not control the engine block temperature since it can not control frictional nor combustion heat. Its job is to try to maintain the engine temperature within a wide range (30-40 degrees). I said "try" because the engine can still overheat or never get up to temperature. The radiator is fully functioning 24/7 even with the engine turned off. The thermostat does not turn it on but merely control the coolant flowing through it. You can remove the thermostat and the radiator would not know the difference.


I'm going to continue to follow up on this, mainly because cooling systems are not as well understood or cared-for the way crankcase oil is (for instance), and a little understanding can go a long way toward making intelligent decisions about maintaining cooling systems and even tweaking for specific kinds of service.

The Man That Can Understand Physics Says:

A car's thermostat controls temperature of the engine's water jacket (albiet within limits) by "turning on" and regulating flow of coolant through the radiator.

The thermostat "turns on" the heat exchanger in the same way I "turn on" the little electric radiator in my baby son's bedroom. I flick a switch which allows current to flow in the electric heating element. The element gets hot, and because there is a temperature differential between the air in the room and the electric element, heat is transferred and the air is warmed as the two try to reach thermal equalibrium (but won't because the heating element has a virtually unlimited supply of electricity to maintain its temperature).

A heat exchanger only functions if there is a temperature differential between working fluids. Thus, when a car is cold and not running, or before the thermostat opens after startup, the radiator sits there and does nothing in the same way that my electric heater does when it's not plugged in to the wall outlet.

This is a good reason to have and use a coolant temp sensor that reports the temp of the coolant on the "engine-side" of the thermostat.

K

 

[azsynthetic]

Originally Posted By: Kaboomba


A car's thermostat controls temperature of the engine's water jacket (albiet within limits) by "turning on" and regulating flow of coolant through the radiator.

The thermostat "turns on" the heat exchanger in the same way I "turn on" the little electric radiator in my baby son's bedroom. I flick a switch which allows current to flow in the electric heating element.
K


Not really. The radiator will radiate or absorb heat whether the thermostat is there or not. When you shut off a warmed up engine the radiator is still doing its job in cooling off the coolant and hence the engine. The engine will heat up and cool down the same way whether the thermostat is there or not. The only difference is the temperature range and the time it takes to get to a certain temperature. There might not be any difference at all depending on the operating environment.

 

[azsynthetic]

Originally Posted By: Shannow
Originally Posted By: azsynthetic
At a system level there are many things that contribute to the engine block temperature.


I thought that we were arguing coolant, temperature, and the control mechanism for THAT...which is the thermostat.


You were arguing whereas I was stating fact.

 

[azsynthetic]

Originally Posted By: 440Magnum

But under NO circumstances would it initiate reverse flow through the waterpump and cooling system like he suggested earlier.


You still haven't a clue. When the thermostat is installed backward the normal coolant flow is now in reverse of the direction that the thermostat was designed for. This is the reason why the thermostat will not open until the coolant on the radiator side is higher than the thermostat setting. If there is no coolant leakage then the coolant temperature on the engine side is irrelevant. This is because the wax pellet is now on the radiator side when installed backward. I believe you are one of those that needs a picture to tell the story because technical wording seems to escape you and most shade tree mechanicx.

 

[mechanicx]

The flow is not reversed by reveresing the thermostat. If a thermostat is not opening whether installed properly or backwards, then there is no real flow other than normal flow within the engine through the themostat bypass back to the waterpump. There is some overflow from the expansion of the coolant from heat. I've already mentioned that. Once the t-stat opens regardless of it being backwards, the coolant is going to flow the same way. I think you are mish mashing heat conduction and actual coolant flow.

Coolant doesn't actually flow in reverse when a t-stat is installed normally and it sure can't when it is reversed since most t-stats are reverse poppet.

 

[Shannow]

Originally Posted By: azsynthetic
Originally Posted By: Shannow
Originally Posted By: azsynthetic
At a system level there are many things that contribute to the engine block temperature.


I thought that we were arguing coolant, temperature, and the control mechanism for THAT...which is the thermostat.


You were arguing whereas I was stating fact.


LOL, you're still wrong.

 

[440Magnum]

Originally Posted By: azsynthetic
Originally Posted By: 440Magnum

But under NO circumstances would it initiate reverse flow through the waterpump and cooling system like he suggested earlier.


You still haven't a clue. When the thermostat is installed backward the normal coolant flow is now in reverse of the direction that the thermostat was designed for.


So what you are trying, but completely failing to say correctly, is that the flow as seen by the thermostat is reverse to how its designed to be exposed to coolant flow. That is true. But you said the "coolant flow is reversed" which is utter nonsense, because it implies that the whole system flow reverses.

 

[Gary Allan]

Quote:
The flow is not reversed by reveresing the thermostat. If a thermostat is not opening whether installed properly or backwards, then there is no real flow other than normal flow within the engine through the themostat bypass back to the waterpump.


Yes, as I think I pointed out earlier, he has a failing of many that assume that they know how to communicate with anyone outside of their bubble.

He left off the essential qualifying addendum, "as perceived by the thermostat".

It's a common failing.

For example, my manual with my 486SX, under "how to increase available memory", stated to set the NOEMS (I saw "gnomes"

) in the Autoexec batch file.

"What's a (g)nomes switch ..and how does one set it? No other reference to the NOEMS settings in the manual at all.

In the Berzerker Wars, John found a group of the doomsday machines. He found them in maintenance mode. There, the berzerkers were still programmed to seek out life and to destroy it, but had no definition of life and how it was to be destroyed. John, the clown he was (he would do stuff like hang a sign on a door that read "UNAUTHORIZED PERSONNEL ONLY" - what a joker

) told the idle berzerkers, "Life is sadness ..and you destroy it with humor".

(can anyone top that in taking this thread any further out there??

)