I was having cooling problems with a stock 350, I put in a160 thermo a taraus elec fan it now cools great in town ,took it 450 mile run to the KKOA meet in salina but on the hiway it warms up to 210 but will cool off if i slow down, sounds crazy but do i need a warmer thermostat to slow the coolant down and give the radiator a chance to do it's job?by the way the 65 elky is a pleasure to drive!!!:beers:

No. Actually you ought to be using a 180 thermostat for less sludging and cylinder wear. The idea that you can circulate the coolant too fast to allow the radiator to transfer the heat to the air passing through the radiator is one of those bs urban legends.

Put it to the reduction to absurdity test: If it goes too fast to lose heat; it goes too fast to gain heat. Or, if you slow it down to zero it will transfer heat infinitely fast.

Same idea as wind chill factor. Standing outside in your underwear at 40*F and zero wind might be tolerable for a while; increase the wind to 20 knots and compare how tolerable it would be...

I like my '65 EC too!

My $0.02

I agree with JJ'65 but disagree with why he says it works. A 160° t-stat will just open sooner than the 180° but the total area of restriction in both t-stats is the same when fully open. If the too fast throught the radaitor thing were not true than no t-stat would be best.....and that isn't true. What JJ's says about ...."If it goes too fast to lose heat; it goes too fast to gain heat. Or, if you slow it down to zero it will transfer heat infinitely fast."....that would be true if water or coolant had the an infinite ability to absorb heat energy, but sad to say it isn't.

I agree with JJ'65 but disagree with why he says it works. A 160° t-stat will just open sooner than the 180° but the total area of restriction in both t-stats is the same when fully open.

Got that one correct!

If the too fast throught the radaitor thing were not true than no t-stat would be best.....and that isn't true.

WRONG! Actually the thermostat has no relationship to managing flow for the purpose of cooling capacity at all. The two are actually mutually exclusive in the cooling department per se. The thermostat simply regulates the "operational temperature" of the engine .. that's it! The sole ingredients of the ability to cool are: coolant flow (more is better), airflow (more is better), efficiency of the radiator (this includes such things as size, media, fins etc) and the efficiency of the water jacket (includes such things as internal surface area, internal manifold design etc).... and last but not least the specific heat number of the coolant. That's it!

What JJ's says about ...."If it goes too fast to lose heat; it goes too fast to gain heat. Or, if you slow it down to zero it will transfer heat infinitely fast."....that would be true if water or coolant had the an infinite ability to absorb heat energy, but sad to say it isn't.

Wrong again with all due respect. JJ is absolutely correct!! Speeding up the coolant thru the radiator is in fact what you want to increase the efficiency of the radiator and system. It's a double whammy literally. Speeding the flow will create productive turbulence for one which assures good contact between coolant and surfaces. Slowing the coolant in a "closed system" will only leave coolant in the engine longer.. which means as it approaches it's corrected vapor point it will lose it's ability to absorb heat disproportionately..and will domino into hot spots and therefore gas out and therefore overheat ...yadda..yadda...yadda. Therefore.. it's paramount to run as much flow as one can muster (to the limits of the system to handle such flow obviously).

There are many threads on this very subject.. and many helpful posters have offered very good links. Here's one.. http://www.arrowheadradiator.com/14_rules_for_improving_engine_cooling_system_capab ility_in_high-performance_automobiles.htm if you want to get into a quasi-physics discusion as well as general issues.

Water will transfer heat energy at a certain rate depending upon the temp it is at from the start of said transfer. Cause if what you say is true then why do cars without heaters need a t-stat? I'm sorry but the manufactures are the cheapest bas**** alive and would leave it out if they could save .000000003 cents. Why do racers use a restricter in place of a t-stat if faster moving water would cool better?

Does the thermostat open or close when the engine gets up to operating temperature? Why?

Water will transfer heat energy at a certain rate depending upon the temp it is at from the start of said transfer. Cause if what you say is true then why do cars without heaters need a t-stat? I'm sorry but the manufactures are the cheapest bas**** alive and would leave it out if they could save .000000003 cents. Why do racers use a restricter in place of a t-stat if faster moving water would cool better?

Higher coolant flow will ALWAYS result in higher heat transfer. Coolant cannot absorb heat after it reaches it's pressure corrected vapor point. Furthermore, coolant absorbs heat at a progressively slower rate as it approaches this point. Also another one here to help..http://www.stewartcomponents.com/tech_tips/Tech_Tips_6.htm

Next with all due respect, you have NOT been paying attention or reading what I have given you. Again.. thermostats are devices that are solely for the regulation of "operational temperatures' of the engine. They keep the engine at the "happy 180 degrees" for combustion efficiency (without going into all the physics of that???Again), and this is where the lubricates work the best as well... never mind that moisture gets evaporated from the internals at that temperature as well. THE HEATER HAS NOTHING TO DO WITH IT!

Racers use restrictors to "regulate" their temperatures for their specific application. Usually circle track guys (and I have been one so I know this) will have a whole selection of restrictors to choose from on any given night. The racer WANTS the engine to be at least 200 degrees for all kinds of purposes that I won't go into here... but because the ambient temperatures will differ (one night it's hot.. one night it could be cold) they will use a smaller restrictor to limit the flow to make the water slow down on cool nights to make the motor hotter or visa versa. Now, also just pulling the restrictor out CAN cause laminar flow issues in the radiator. This is extremely inefficient. With the large restrictor their causing turbulence... this will eliminate the worry of laminar flow and the added turbulence makes the system more efficient.

That's the physics... at least where I went to thermodynamic school!

Higher coolant flow will ALWAYS result in higher heat transfer. Coolant cannot absorb heat after it reaches it's pressure corrected vapor point. Furthermore, coolant absorbs heat at a progressively slower rate as it approaches this point. Also another one here to help..http://www.stewartcomponents.com/tech_tips/Tech_Tips_6.htm

Next with all due respect, you have NOT been paying attention or reading what I have given you. Again.. thermostats are devices that are solely for the regulation of "operational temperatures' of the engine. They keep the engine at the "happy 180 degrees" for combustion efficiency (without going into all the physics of that???Again), and this is where the lubricates work the best as well... never mind that moisture gets evaporated from the internals at that temperature as well. THE HEATER HAS NOTHING TO DO WITH IT!

Racers use restrictors to "regulate" their temperatures for their specific application. Usually circle track guys (and I have been one so I know this) will have a whole selection of restrictors to choose from on any given night. The racer WANTS the engine to be at least 200 degrees for all kinds of purposes that I won't go into here... but because the ambient temperatures will differ (one night it's hot.. one night it could be cold) they will use a smaller restrictor to limit the flow to make the water slow down on cool nights to make the motor hotter or visa versa. Now, also just pulling the restrictor out CAN cause laminar flow issues in the radiator. This is extremely inefficient. With the large restrictor their causing turbulence... this will eliminate the worry of laminar flow and the added turbulence makes the system more efficient.

That's the physics... at least where I went to thermodynamic school!


Steve
YOUR THE MAN !! ONCE AGAIN .
Now for us lame dudes ... can you give a discription of laminar flow ..I have seen you mention it a number of times but not sure of the definition .
thanks Don

The advent of water cooled computers has generated some good studies of cooling systems. Here's an article titled:

"Watercooling Physics - Laminar and Turbulent Flow"

There have been several studies that show that for the same net flow of fluid through a channel, a turbulent flow can transfer as much as 150-500% more heat.


http://www.overclockers.com/articles511/index.asp

Steve
YOUR THE MAN !! ONCE AGAIN .
Now for us lame dudes ... can you give a discription of laminar flow ..I have seen you mention it a number of times but not sure of the definition .
thanks Don

Com'on Don... stop it! You're gonna make my head too big! And.... I disagree.. I don't think anyone is lame here at all! WE all learn from each other.. and while thermo and electrical stuff are MY forte.. I often need help from others on other things (like paint!!). So, I am just trying to keep folks straight here in the cooling and electric forums which I know well. There is so much misinformation out there in these areas and it's a commonly misunderstood subject(s) with lot's of conclusions absolulutely being off or misread. I just try to keep us on track, that's all. And, if I come off flip once in awhile... it's just that we have been thru some of this stuff so many times.... I don't see how it resurfaces with regularity. But, the encouraging thing is I see others that are well tuned to the "truth" about this stuff and chime in on a regular basis. I hope I have affected some of them with the facts.

Okay.. laminar flow! I have the perfect analogy for "laminar flow".. Think about that favorite lake or river that you would oft during those hot days of summer. Now.. remember jumping in the lake and even tho that lake is fed by flowing tributaries, streams or rivers..... the surface of the lake was always warm and yet just a few feet down at your feet the lake was MUCH colder. Now, even tho the body of water is flowing (ever so slowly) and the surface is being warmed by the atmosphere and sun, the entire body of water is flowing such that there is NO mixture... no turnover..no agitation at all... and such labelled .. no turbulence. The water at the bottom is not forced against the surface atmosphere and remains cool. Or .. in reverse the warm surface water is not forced agains the bottom surfaces for cooling either. So, the lake is stratosphered or layered with different temperature ranges and is experiencing this "laminar flow" or "layered" (as in temperature) flow.

To take that analogy to an automotive cooling system, every flowing channel whether large or small is subject to laminar flow if the coolant is flowing slow enough and moreover has smooth walls such as tubes thru the radiator. This is where it's more prevalent (radiator tubes) than any other spot even tho it can happen in the block too (the block is mostly comprised of rough edges and cast walls that cause agitation and turbulence). Water entering from the radiator exit hose can come out so smoothly and non-agitated to the extent that it flows thru the radiator without many of the center-core coolant molecules being forced against the outer most tube surfaces which means that "core" of coolant remains hot...uncooled and uneffective at cooling when it returns to the engine. So, the idea is to induce agitation or turbulent flow so that all the coolant molecules will be forced against the walls of the tubes effectively transfering all the heat that you can transfer. Works the other way too.

Here is picture of laminar flow...and a comparison of turbulent flow.

http://www.cvphysiology.com/Hemodynamics/H007%20turbulent%20vs%20laminar%20flow.gif

The shear design of radiator tubes (elongated) aid and abet this turbulent flow as well. The elongated designs will help the coolant (in the center) be forced agains the outside surfaces as opposed to just simple round ones where "core flow" sets up often creating pure laminar flow issues. Also, dimpling will help induce turbulent flow as well. Again.. same idea. ... baffles in the radiator.... same idea. All in the name of causing coolant agitation to increase system efficiency.

Now, while turbulence is a wanted feature of any cooling system... the other factor to the "flow" issue is that the higher the flow... the more turbulence that gets induced and hence the lower the likelihood of laminar flow issues. Take for example this simple analogy. Water around bridge supports. In the summer (or when water levels are low) when the river is flowing slowly the water goes smoothly around the bridge support legs. In the winter (or when the water is at higher levels) the flow is faster, so the flow may start off laminar and smooth flowing...but quickly separated from the leg and becomes turbulent.

Same thing happens in your engine cooling system. The increase in flow (as I say it's a double whammy with turbulence being one wanted feature) will cause agitation all over the system not just the radiator. The internal block cooling manifold tubes, races and chambers will become more tubulent, the exit at the thermostat will become highly agitated and the coolant entering the radiator will have highly agitated and diffused molecules that carry that agitation all the way to the other side of the radiator thru the tube system. Even smooth wall surfaces become agitated. This is because the coolant at the outside edges or in contact with the smooth walls have more friction to the molecules than the molecules at the center of the tubes that are suspended in coolant. The added friction at the contact surfaces of the tubes pull on the molecules while the center of the coolant stream flows more freely. This gets exaggerated as the flow increases thru the tube. The higher the flow the more mixing that starts to take place. This if the perfect storm for high efficiency cooling.

MOre to the exit at the intake or thermostat housing. If you leave the exit un-effused and the coolant to flow evenly and uninterrupted thru the upper hose (the mechanics of the upper hose under flow conditions actually aid and abet laminar flow set up because it collects all the output from the exit and linearly guides it for some distance causing in a smooth cavity that flows just in one direction) the coolant dumps into the tank (whether side or top) relatively unagitated and unchaotic. This is very inefficient as we learn here. The idea of the thermostat is to not only be the "keeper" of the engine "working operational temperature" range, but to provide a port of turbulence induction to the upper hose and radiator tank system (I bet you never knew that one!). Anyway, by removing the thermostat.. the flow is relatively uneffected. By using one, the flow is much more agitated and effective. Same thing with the reducers by the way in racing systems.

Now, can you get too much flow to reduce cooling? Theoretically no...but, design wise yes. There are DESIGN limitations to any cooling system where eventually increasing the flow will induce other issues that reduce the efficiency of the system. It has nothing to do with "flow" itself, but moreover what the increase in flow is causing mechanically. Going back to the model of coolant flowing thru the cooling system manifold.. the coolant can become so turbulent that unproductive eddys can form or the commom form of "cavitation" can occur inducing air and literally foam the coolant. Coolant flowing past small chambers and/or around sharp bends or edges in the coolant jacket can literally "wring" air out of the coolant causing air to be induced in the system which is a huge NO-NO! This was commonly the case in the old style waterpumps where the impellers where relatively poorly designed and at high rpms the pumps were cavitating like all get out. Hence, the invention of the "underdrive pulley" system with racing applications where the rpms are typically stratospheric in nature. The waterpumps were reduced in rpms to keep them from cavitating moreover.

Don, one of the added features that you could add to your radiators is tank baffles. These baffles would be designed and/or placed in strategic positions to turn over the coolant on the top or side tanks. They could be simple large fins that protrude in the tank space alone breaking the entering coolant as it falls to the bottom of the radiator creating chaos in the molecules. Very few radiator manufacturers do this... due to their own laziness.. and could be an "advertised" and "differentiating feature" of your product. Industrial coolers do this all the time.... and I would be glad to offer some help in simple designs that would be cheap and effective to do in your products.

So, that's my story ... and I'm stick'n to it!

i do have a question
instead of a problem that needs fixed ,its a fix that worked for me just want to know why,,hopefully
to start with it was a 1961 gmc 4x4,,,mild 350 4 sp running stock gm flex fan and stock 3 row down flow rad
my symtems were over heat on trail and at idle,,,,,would cool down when on the road at cruize,when off roading it would over heat to the point i had to shut it down
tried a 160 tstat,,,would do the same
180 tstat still the same
195 tstat,,,it would run 190 to 195 all the time no mater where i went
so my question would be why running a hotter tstat create a better overall cooling effect on my truck?

Got that one correct!...

WRONG! Actually the thermostat has no relationship ......

Wrong again with all due respect. .....

Com'on Don... stop it! You're gonna make my head too big! ....

I always thought that our purpose here was to share our experience and mentor those who are less experienced. Let's see if we can get back to doing what this sight was created for, helping each other....and put the egos aside. This is not a contest and we are NOT stupid. By the way, Thanks for all the great information. THAT is of great value.

Chuck

so my question would be why running a hotter tstat create a better overall cooling effect on my truck?

I would say because the stat would actually be able to close for a period of time allowing the water to release more heat as it passed thru the radiator at a slower rate. With the 160/180 rating the stat would never see enough of a temp reduction in the coolant to close or partially close. The difference would be greater at low speeds where airflow over the radiator core is low.

I would say because the stat would actually be able to close for a period of time allowing the water to release more heat as it passed thru the radiator at a slower rate. With the 160/180 rating the stat would never see enough of a temp reduction in the coolant to close or partially close. The difference would be greater at low speeds where airflow over the radiator core is low.

Does the water in the engine get hotter when you slow the flow to allow it to get colder in the radiator? How would this added heat in the water indicate on the temperature gauge? Would it show hotter or colder?
Maybe the air is going through the radiator so fast it doesn't pick up any heat?

I always thought that our purpose here was to share our experience and mentor those who are less experienced. Let's see if we can get back to doing what this sight was created for, helping each other....and put the egos aside. This is not a contest and we are NOT stupid. By the way, Thanks for all the great information. THAT is of great value.

Chuck

I am assuming that you are aiming your attack (or whatever you want to call it) at me. I think I stated it pretty clearly and factually really. I really don't have an ego here... and if you read what my response is to Don and take that perspective.. it is what it is. I did admit to being "flip" once in awhile.. because there is so much misinformation that is passed on without doing homework on this very same site. I have posted this very information literally dozens of times here over and over. So, I just state the facts.. and my take is that if you don't know what you are talking about regardless of their personal experience........ don't offer help to others causing them to take actions that could be either wrong, spend their money fruitlessly... or moreover dangerous. And..we all know... overheating issues can be dangerous needless to say.

And.... I am not into PC bs .... trying to make "everyone" happy and get along per se esp if they give bad advice...because it can be dangerous. I don't pick on others just to pick on them. On the other hand.. I usually use the phrase "with all due respect" which shows that I do respect their experiences and words. I know their personal experiences can seem to them one thing.. but can or are really another. I don't know how much clearer I can make it really. If you don't like my words and/or approach.... just say so and I will take a hike!

Does the water in the engine get hotter when you slow the flow to allow it to get colder in the radiator? How would this added heat in the water indicate on the temperature gauge? Would it show hotter or colder?
Maybe the air is going through the radiator so fast it doesn't pick up any heat?

Yes... yes.. yes! YOu've got it! Water that is slowed thru the radiator is also slowed thru the engine cooling manifold picking up heat, but at a lesser and lesser rate as the coolant races towards its corrected vapor point. You would see a hotter temperature at the gauge because of the slowing of the coolant in some instances if the thermostat were to be completely open for example.

Air flow is like coolant flow. Think about it. Do you want lot's of air cooling off an object.. or just a slight flow of air. YOu want more air because the ambient air is an "open" system that always has an ample supply of relatively cold/cool air. So, the temperature difference is great.. and the more the better.

You're preaching to the choir here, Steve. I think that there are some common misconceptions and assumptions that lead to wrong conclusions about what really happens in a cooling system.

Take for example a restrictor. What is the real effect of a restrictor? Has anyone actually measured the system flow difference after an installation? Does it introduce more turbulence? Does it affect the pressure in the block? Does it affect the operation of the water pump?

Another misconception is the function of time in the system operation, the belief that the coolant needs a certain amount of time in the radiator to cool off or a certain amount of time in the block to get hot. The only function of time in the system is the rate of heat rejection per unit of time, if you're making 100 units of excess heat per second in your engine, you have to reject 100 units of heat per second in your cooling system to maintain a heat balance.

Let's look at the posts involving the swapping of thermostats from a 180° to a 195° and the resultant lower indication of engine temperature. The hypothesis seems to be that the 195° thermostat is somehow modulating the flow so the water has more time to cool, which proves to be a faulty assumption.

If you kept all the other variables the same, as in same engine power, same air temperature, same air speed, etc., you would need the same average radiator temperature in order to reject the heat. Average radiator temperature is roughly inlet temp minus outlet temp divided by two. We don't normally monitor the outlet temp but the engine temperature gauge is a good indication of the inlet temp. At a constant balanced heat load, a reduction in inlet temperature has to be accompanied by an increase in outlet temperature, and the only way to accomplish that is to have an increase in effective coolant flow through the radiator.

I always thought that our purpose here was to share our experience and mentor those who are less experienced. Let's see if we can get back to doing what this sight was created for, helping each other....and put the egos aside. This is not a contest and we are NOT stupid. By the way, Thanks for all the great information. THAT is of great value.

Chuck

Steve dont take offence to that .. i didnt get what he was talking about either .. Sorry chuck .. i asked a Question and Steve informed me and everybody on this forum .. as far as im concerned his word is gold ..we could all take a lesson from him .

Steve dont you dare go any where !

.....I did admit to being "flip" once in awhile.. because there is so much misinformation that is passed on without doing homework on this very same site. I have posted this very information literally dozens of times here over and over.

I couldn't agree more Steve. The most frustrating part of being a support person here, and many other sites, is that people often don't use the search feature and the same questions get asked over and over. I feel your pain. My only issue is that we should try to be a "little" PC so we don't chase off users who don't know the answers. I would also ask the users to search first and ask second so we keep smiles on the faces of our technical experts.

I'm really an electrical and engine guy, but I am here on this forum to help out. In fact you guys helped my solve my heat problems about 4 months ago. Now it's "dead on" 190 all the time. I know just enough about this subject to be dangerous, but I do know that you and Don are a huge asset to TC. Sometimes I feel like a darn traffic cop. Thanks so much for your support..... and let's all try to keep a smile on our faces.

Chuck

I couldn't agree more Steve. The most frustrating part of being a support person here, and many other sites, is that people often don't use the search feature and the same questions get asked over and over. I feel your pain. My only issue is that we should try to be a "little" PC so we don't chase off users who don't know the answers. I would also ask the users to search first and ask second so we keep smiles on the faces of our technical experts.

I'm really an electrical and engine guy, but I am here on this forum to help out. In fact you guys helped my solve my heat problems about 4 months ago. Now it's "dead on" 190 all the time. I know just enough about this subject to be dangerous, but I do know that you and Don are a huge asset to TC. Sometimes I feel like a darn traffic cop. Thanks so much for your support..... and let's all try to keep a smile on our faces.

Chuck

Okay... group hug!http://www.maj.com/gallery/DanElHombre/smilies/friends.gif

Steve,.....Just keep bringing the facts. I'm not so thinned skinned that I can't be called wrong every so often. Particularly when I can learn something from someone who actually knows what he's talking about. Your certainly correct about bogus info being dangerous. Unfortunitly, there's a lot of "a friend told me, I think this will work and try this" BS info on this site. I've been doin this stuff for 35 years and I don't offer advise unless I have either experienced the problem and found a fix, or have documented, factual information. Those less experienced would be wise to listen to what Steve Jacks has to say. He knows of what he speaks.
And Thanks, but I ain't doin no group hug!

blksheep:)...properly vented...in Charlotte

....and I was sooo hoping for a group hug!

The problem is that everyone really wants to help and , as a result, a lot of bad data gets posted. It's all done with the best of intensions but, I always wait a couple days before implementing a suggested fix. By then someone who knows the REAL fix has set me (and the incorrect poster) straight.

I think you have the best suggestion, blksheep. If you are not sure the answer is correct, don't post it.

Chuck