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Thermostat misinformation?

Discussion in 'The Hokey Ass Message Board' started by miller, Sep 10, 2010.

  1. miller
    Joined: Aug 5, 2006
    Posts: 401

    miller
    Member
    from New Jersey

    ..... I have read some posts on this site and other sites where the writer is having a running hot problem...the writer would say some thing like this ..my car is running TO HOT it reads 210 degrees and I have a 195 thermostat in it..I want it to run cooler....another person would write a reply stating that he should change the thermostat to a 160 degree........The problem I see here is what will a 160 do that a 195 is not doing when it comes to lowering the 210 temp?....Once the thermostat reaches its setting 160/195 it will open and stay open unless the coolant temp drops below the 160 or the 195.....And when the coolant/temp reaches 210 it does not matter what temp. the thermostat is set/rated for...The coolant temp is 210.....A thermostat is closed when the coolant temp. is below its setting and opens when it reaches its setting so how would a different temp thermostat change any 210 temp?..........Miller
     
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  2. shinysideup
    Joined: Sep 1, 2008
    Posts: 1,627

    shinysideup
    BANNED
    from ruskin, fl

    Yep. People will give advise on subjects they cannot grasp.
     
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  3. Hnstray
    Joined: Aug 23, 2009
    Posts: 8,439

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    Yep, common advise, but exactly as you point out, it is incorrect.

    A similar thing happens when a person enters a car that is either too hot or too cold and cranks the heat/AC control full in whatever direction they want to move the temp. But the normal setting will bring the heat up or down to the desired temp. The extreme settings do not necessarily make it happen any quicker unless one uses 'recirculate or max'.

    Ray
     
  4. Road Runner
    Joined: Feb 7, 2007
    Posts: 1,220

    Road Runner
    Member

    A thermostat sets the minimum temperature - that's all.
    Helps especially at lower outside temperatures to get the engine temp high enough to operate properly.
     
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  5. bigdog
    Joined: Oct 30, 2002
    Posts: 402

    bigdog
    ALLIANCE MEMBER

    Yep, thermostat controls the low end of operating temp. But there is a difference between thermostats. At work we sell a standard and a premium line. The premium line has a larger valve opening so it can flow more coolant- mre flow= better cooling. You get what you pay for.
     
  6. Hnstray
    Joined: Aug 23, 2009
    Posts: 8,439

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL


    While that is functionally true, theoretically, it also sets the operating temperature and maintains it. Again, theoretically, the cooling system is supposed to have the capacity to cool the engine adequately so the temp does not exceed the thermostat design operating temp.

    Ray
     
  7. Road Runner
    Joined: Feb 7, 2007
    Posts: 1,220

    Road Runner
    Member

    'Mr. Gasket' offers a good high-flow thermostat design, that flows more, has a tiny bleed hole and stays open in case of failure, unlike standard ones who can get stuck in the closed position.
     
  8. Road Runner
    Joined: Feb 7, 2007
    Posts: 1,220

    Road Runner
    Member

    I also often read that another purpose of a thermostat is to restrict flow through the radiator, for better cooling. But that means that coolant inside the engine heats up further at the same time, so I am rather skeptical.
    Radiator size, amount of cores and general design and materials used, should match the engine and use, I would think.
    Type of coolant (ability to absorb and dissipate heat) also matters, just as outside temperature and humidity.
    The better the flow in general, the better the cooling effect makes sense to me.
    But I could be wrong and always like to learn something new.
     
  9. Hnstray
    Joined: Aug 23, 2009
    Posts: 8,439

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    There is the possibility of the coolant flow being too great and passing through the radiator faster than adequate cooling (heat transfer) can occur. Then you are pumping too hot water back into the engine and it's ability to absorb excess heat is already partially compromised and, again, it's flowing too fast to absorb what it can from the engine. Viscious cycle. So, yes, a lot of factors enter into a well designed cooling system.

    Ray
     
  10. Road Runner
    Joined: Feb 7, 2007
    Posts: 1,220

    Road Runner
    Member

    Makes sense.
    Years ago, I experimented running without a thermostat, as recommended by several So-Cal old car experts.
    I chose one of the hottest summer days and drove almost an entire day on the freeways.
    There was no difference, as compared to running with a thermostat, except the temp came down a little quicker after a climb.
    However at the end of the day, when the sun went down, the engine temp fell below 180, during the last few miles before I reached home.
    Since then I have always used a 180 thermostat (high flow type) year round.
     
  11. AlbuqF-1
    Joined: Mar 2, 2006
    Posts: 910

    AlbuqF-1
    Member
    from NM

    I copied this off a forum, not sure but I believe it was the Ford Trucks Forum. At any rate, it is a phone interview with a Stant thermostat engineer -- can't beat that. It isn't as simple as you'd think:
    ............................
    "I had a nice conversation with Paul Miglierina, at Standard-Thomson Corporation, 152 Grove Street, Waltham, MA 02254-9109 (781-894-7310). They are a division of Thomas Industrial and Automotive, and make the automotive thermostats sold under the Stant and Gates brand names. He seems to be a great guy; he has a lot of experience and is very knowledgeable about both the practical and technical aspects of how thermostats work. I actually had two conversations with him - I had to call him back to confirm some information, since I was typing at warp ten during our first conversation. He indicated he would be happy to answer any additional questions that anyone may have.

    I specifically asked if I could get some detailed performance curve information – temperature versus thermostat opening position. Paul indicated that each manufacturer uses proprietary design methods, and while he would gladly discuss the general operation of thermostats, he could not provide detailed design data. Fair enough. Here is a condensed version of our conversations in a question/answer format.

    George: Our group has had some discussion that thermostats are basically on-off devices. The thermostat is there only to help the engine reach operating temperature quickly. Once it opens, it's no longer a "player" in the system since the engine should reach an ideal operating temp close to 210 degrees. Do we have that correct?

    Paul: Well, that's partially true. The thermostat does stay closed until the coolant temperature reaches the nominal thermostat opening temperature. After that, the thermostat also regulates coolant flow to maintain the engine temperature in the optimum range. At Standard-Thomson, we talk about four temperatures when we design and test thermostats - other manufacturers may have other terms or methods of designing and testing their thermostats. In increasing temperature order, our temperatures go like this:

    Minimum opening temperature - below this temperature, the thermostat must remain closed.
    Nominal temperature - the number you read on the box, or are quoted as the thermostat rated temperature.
    Maximum opening temperature - at this temperature, the thermostat must be open at least a minimum amount (0.003”, 0.005”, etc.) specified by the manufacturer.
    Full open temperature - the temperature at which the thermostat is at its rated full open position (0.300”, 0.400”, etc.).

    The range between the minimum and maximum opening temperature is typically around 5 to 7 degrees F, although specialized thermostats for high-performance applications may have a much narrower range. All of our thermostats must begin to open within this range, or they are rejected for failure to meet quality assurance.

    George: So, if we are driving down the road under normal conditions, the thermostat is in the full open position, correct?

    Paul: No. We work with the OEMs to ensure that, under normal operating conditions, the thermostat is NOT at its full open position. The thermostat is designed to keep the engine in a narrow temperature range while it is operating. Let’s use an example. If we design a thermostat with a 0.300” full opening stroke, we may want it to operate at about 0.200” open stroke under normal conditions. If you start up a big hill, or start towing a load, the engine puts out more heat. We need to be able to open the thermostat more, say to 0.250”, so there is more coolant flow to remove the extra heat from the engine.

    George: So you design thermostats to keep engines in a narrow range of temperatures over their various operating conditions. What engine operating temperature range do you shoot for when designing a typical thermostat?

    Paul: You should realize that, when we design a thermostat, we work with a large number of variables including the type of coolant, the ambient temperature and humidity, engine heat generation, radiator capacity, water pump pressure, and at least a dozen more. There is no single temperature curve for all thermostats with a nominal rating of 180 degrees, or any other nominal temperature rating for that matter. Many common thermostats are designed to regulate the coolant in the range of 205 to 215 degrees – although thermostats designed to operate outside that range are certainly not rare. As I said, the precise temperature depends on many factors. Remember that the thermostats are not fully open when they are regulating in their design range, or they wouldn’t be able to regulate the engine temperature.

    George: What is the typical full open temperature for a thermostat?

    Paul: Again, it varies a great deal. There is no single full open temperature for all thermostats with a given nominal rating like 180 degrees. Full open temperature can range as high as 300 degrees. I’m not saying a common engine will ever run at that temperature, but the thermostat performance curve may end with the full open temperature at 300 degrees in order to get the performance we need at lower temperatures where the engine is actually operating.

    George: Sorry to beat this to death, but I want to make sure I understand this clearly. If I change from a 180 degree to a 195 degree thermostat, will my engine run hotter under normal conditions?

    Paul: No, that’s fine. Remember that there is no single temperature curve for all thermostats with a nominal rating of 180 or 195 degrees. You could buy a 195 degree thermostat that is designed to regulate at the same temperature as your original 180 degree thermostat. In that case, you would see no difference in the engine temperature under normal operating conditions. You would, however, see that the engine gets warmer before the thermostat initially opens.

    George: So, if I have a 180 degree thermostat, and I want to increase my engine operating temperature under normal driving conditions, how do I know which 195 degree thermostat to buy?

    Paul: I don’t think you will easily find the information you need to do what you are asking. Performance curves for thermostats are generally proprietary information for manufacturers. Some customers probably have increased their engine operating temperature by trial-and-error, and found a part number that does what they want to do. You may get lucky on your first 195 degree thermostat purchase, and never realize that any old 195 degree thermostat may not provide the same results.

    One suggestion is to try different 195 degree thermostats in your engine and monitor the normal operating temperature with an accurate temperature meter. As you mentioned, these thermostats are not expensive parts, so you could pick up a few 195 degree thermostats with different part numbers without a big dollar investment. If you have a temperature gage in your instrument cluster, you can get a very rough sense of any changes with different thermostats, but those gages are not very good for absolute temperature measurements.

    The other suggestion I can make is to measure the temperature curve for a few thermostats yourself. The measuring equipment may be a cost issue, unless you have access to a lab that can do it for you. When we test our thermostats, we use carefully stirred fluid baths to make sure we don’t have temperature gradients in the fluid. We also use thermocouples attached directly to the thermostat housing to get very accurate temperature measurements – you can’t be off by five degrees when doing this. You also need to set up a device to measure the opening movement of the thermostat. A dial indicator is accurate enough and works well if you put together some sort of fixture to hold the thermostat and dial indicator in place. One other thing – you can’t use plain water for this type of work since it boils at too low a temperature. We use fluids specifically designed to be environmentally friendly and non-toxic for our employees. I haven’t looked, but an internet search would probably get you in touch with suppliers of fluids for this type of testing.

    George: One final question – and this may be something you can’t answer. Some of our folks have found that removing the thermostat actually causes the engine to run hotter. Most of us agree that this seems counter-intuitive, but it certainly appears to be the case. Do you have any comments on this – or should I contact a radiator manufacturer?

    Paul: Well, I don’t know why that occurs. Off the top of my head, it might have to do with the coolant bypass passage in the engine not being closed when the thermostat is removed. I really haven’t got any other information for you on that question."
     
    Last edited: Sep 10, 2010
  12. 4t7flat
    Joined: Apr 15, 2009
    Posts: 266

    4t7flat
    Member

    One thing,you want to be sure the T-stat you use is made in USA. If it does not say "Made in USA",it is most likley made in China. I have seen many failed T-stats in recent years that were made elsewhere. The company selling them,won't print on the stat itself where it was made. If they are proud of their product,they will tell you where its made.
     
  13. forty1fordpickup
    Joined: Aug 20, 2008
    Posts: 250

    forty1fordpickup
    Member

    Don't forget there are 2 major heat transfers. First is block to coolant. Second is coolant to air through the radiator. The thermostat will regulate the first. The second requires adequate air flow through the radiator. On some vehicles the air flow though the radiator is a problem when moving slow or stopped. Ross's post is correct as to the function of the thermostat. The second piece of the puzzle: Is there enough air flow to carry the heat away from the radiator?
     
  14. Dyce
    Joined: Sep 12, 2006
    Posts: 1,641

    Dyce
    Member

    ^^^ what he said^^^
    I installed 3 different thremostats in my wifes Explorer. She froze her ass off for almost 2 winters because the engine wouldnt heat up. All 3 were Stant. I was talking to a guy at work about it and he said to put a Motorcraft thermostat in it. I thought he was full of shit, but did it anyway. Guess what? The heater kicked ass and I was a hero;).
     
  15. Very true, and this question can even be split into two parts- one of which is very often ignored:

    1) Is there sufficient air flow into the radiator?

    2) Is there sufficient air flow out of the engine compartment?
     
  16. larry_g
    Joined: Feb 21, 2010
    Posts: 25

    larry_g
    Member
    from oregon

    Years ago I was working a V-8 Corvair and trying to sort out the cooling that was not cooling to well. A coworker put me on the phone with a GM cooling engineer. His advise was to put in a 210 or 220 degree thermostat. His reasoning as stated above was to slow down the flow so that it had enough time in the radiator to transfer the heat out and time in the block to absorb heat. He also went into the heat transfer from hot to cold. The larger the heat differential between the cooling air and the radiator the more BTU of heat can be transfered. I followed his advise and the higher temp thermostat kept the system from running away. With lower temp thermostats or none the system would continously build heat till it blew.

    It worked for me, YMMV.

    lg
    no neat sig line
     
  17. budd
    Joined: Oct 31, 2006
    Posts: 3,479

    budd
    Member

  18. Flat Ernie
    Joined: Jun 5, 2002
    Posts: 8,398

    Flat Ernie
    Tech Editor

    This is more in line with the myths out there. The longer you keep the coolant in the radiator, the longer it is in the engine block absorbing heat. You gain nothing.

    Only two things in the cooling system increase cooling - more flow and a bigger radiator (heat transfer).

    Look at all aftermarket water pumps - what do they have in common? They flow more water.

    Look at the evolution of the flathead water pumps - 3 vanes, 4 vanes, 6 vanes - why? More flow. Look at all "modern" flathead pumps (Skip's, Speedway, etc) - more flow.

    Look at any of the "kits" (like flow kooler) to improve water pumps - more flow.

    There are some arguments to be made for the t-stat acting as a restrictor to produce some resistance to the pump within the engine to help reduce localized boiling of hot spots by increasing water pressure.

    The engine needs to get to operating temp as quickly as possible for efficiency reasons. I'm not talking mpg efficiency, I'm talking about thermal efficiency. There is also an optimum temperature range for maximum efficiency. An OEM designed system is striving for this and it's what that dude in the interview above is talking about.

    If your engine is overheating, there is a problem somewhere. If it's not engine related (cracked block/head, blown head gasket, retarded timing, etc), it is in the cooling system. Radiator is too small, isn't flowing (blocked), or has an airflow problem (ducting, shrouds, fan clutch, fan size/placement, etc) or water isn't flowing (slipping belt on water pump, broken impeller, collapsing hose, obstruction, etc).

    Theory aside, I've seen different engines/applications respond to different things that don't seem to make sense in line with theory...;)
     
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  19. B Blue
    Joined: Jul 30, 2009
    Posts: 281

    B Blue
    Member

    Flat Ernie, you are correct in that water held in the radiator means that water is held longer in the block, so the extra cooling is zero.

    HOWEVER, there are situations where slowing water velocity gives extra cooling. As water flows through a radiator, hose, pipe, block, you name it, if the velocity gets above 10ft/sec, it cavitates. Bubbles form, causing the water to loose contact with radiator (or block) and cooling capacity goes into the toilet. Thus, running a high capacity pump at high rpm and no flow restriction can lead to cooling problems.

    Another point, never judge the water temp with a dash gauge. I have good luck with a candy thermometer stuck into the cold radiator, then start the car to get a true temp. Of course, the infrared thermometers work fine.

    Final fallacy, a thicker radiator will cool better. Not if the air is heat saturated when it leaves the thin radiator.

    Bill
     
  20. Diavolo
    Joined: Apr 1, 2009
    Posts: 798

    Diavolo
    Member

    One point to consider that is not thermostat related which flat ernie made note of:

    Fan clutches get old and wear out. My ot daily was overheating slightly (210+) and the thing sounded like a plane trying to take off when it did. Replaced the fan clutch with a cheap parts store one and the temp stays just under 200, with a 195 stock thermostat. Still sounded like a plane. Replaced it with a dealership item. Same result but no more fan noise.

    Also, radiator caps hold the coolant under pressure which raises the boiling point so that coolant stays liquid at the block. Without the right radiator cap with the correct pressure rating for your application, you are going to have problems keeping things as cool as they can be.
     
  21. 29nash
    Joined: Nov 6, 2008
    Posts: 4,544

    29nash
    BANNED
    from colorado

    Yep; You are correct Flat Ernie. If the coolant is still so hot as it's leaving the radiator that it won't maintain a consistent regulated temperature in the water jacket, that consequence is due to;
    1) inadequate flow of coolant(lots of causes for that),
    or
    2)inadequate airflow(lots of causes for that),
    or
    3) inadequate radiator frontal area.

    Changing the value of the thermostat (or removing it entirely) will not remedy any of the three.
     
  22. B Blue
    Joined: Jul 30, 2009
    Posts: 281

    B Blue
    Member

    Did you read my post? The flow rate can be too fast but it has nothing to do with retention time.

    Bill
     
  23. canman
    Joined: May 6, 2010
    Posts: 112

    canman
    Member

    Actually the speed of the coolant through the radiator has less to do with the temp. then the cavitation caused by that fast coolant going past angles in the coolant passages,dropping the pressure. The speed can be controlled by pump design and pulley size better than thermostat opening size.
     
    Last edited: Sep 11, 2010
  24. Road Runner
    Joined: Feb 7, 2007
    Posts: 1,220

    Road Runner
    Member


    There we go.
    Thanks for your explanation, Ernie.

    I agree, judging from my own experiments with 2 core vs. 3 core radiators and running with 160, 180 thermostats, high-flow type and without any.
    The larger radiator and greater flow gave the best cooling for higher engine and outside temperatures.

    I also experimented with different design thermostats in hot water on the stove and some have a wider opening (more flow) at maximum open operation than others.
    Interestingly the premium stainless type had less flow at max, compared to the standard type.
    The high-flow type had the best design with the widest opening at max.
     
    Last edited: Sep 11, 2010
  25. B Blue
    Joined: Jul 30, 2009
    Posts: 281

    B Blue
    Member

    You sure are a hardheaded bunch of guys, aren't you?

    Bill
     
  26. 39 All Ford
    Joined: Sep 15, 2008
    Posts: 1,531

    39 All Ford
    Member
    from Benton AR

    You are dead on on the whole thing, people like an easy fix, few things are an easier fix than a thermostat.

    Did you ever hear the one about the guy looking for his keys under the street light.....

    Besides, almost any engine is going to run better, longer, and stronger at 195 vs. 160
     
  27. budd
    Joined: Oct 31, 2006
    Posts: 3,479

    budd
    Member

    i have run cars with the thermostat removed only because they had stuck on me, summer or winter, in town or on the highway they always ran cooler, usely to cold, but dam near every autoparts store sell these plates made to replace a thermostat, are they totaly pointless?

    http://gmperformance.racerswholesale.com/product.cfm?InvKey=28487
     
  28. larry_g
    Joined: Feb 21, 2010
    Posts: 25

    larry_g
    Member
    from oregon

    I have to disagree with the first statement. Think of this as a transfer of energy. It takes time for the heat to move from one medium to another, engine to coolant, or coolant to air. Think if your trying to run at 160 degrees and crossing the hot desert. You may have only a 30 degree difference between the air and the coolant. Not much transfer of energy is going to happen. Raise the coolant temp and more energy transfer will happen. If your system is marginal then holding coolant in the radiator longer will allow it to dump more BTU's out and the hotter coolant coming from the engine will set up the greater differential between the cooling air and the coolant.

    lg
    no neat sig line
     
  29. Road Runner
    Joined: Feb 7, 2007
    Posts: 1,220

    Road Runner
    Member

    Found this article online:


    <TABLE border=0 cellSpacing=0 cellPadding=0><TBODY><TR><TD height=97 vAlign=top width=696 colSpan=29 align=left><CENTER>Cooling system tips centering around the most overlooked component in the loop&#8230; the Thermostat
    </CENTER>

    Any internal combustion engine incorporating a closed liquid coolant system, needs a thermostat. This not only regulates the temperature, but also the water flow during the open cycle of the thermostat. Too much flow can pass the water too quickly over the coolant jackets not absorbing maximum heat transfer. Too much flow prevents the coolant from spending enough time in the radiator to allow efficient liquid to air heat transfer. Too little flow can overheat the coolant before it gets a chance to radiate it's heat stored in it's mass. If coolant flows too fast as in the case of no thermostat being present, the coolant can leave air pockets in


    </TD><TD colSpan=5></TD></TR><TR><TD height=7></TD><TD colSpan=25></TD><TD height=308 vAlign=top rowSpan=4 width=226 colSpan=11 align=left>the nooks and crannies in the cylinder heads, thereby "superheating" into an expanding gas, which forces water out of the overflow even though the water leaving the engine appears to be well below it's boiling point. This is a dangerous situation leading to serious engine damage due to cracked heads and cylinder blocks, without warning.


    Some reasons racers have deleted the thermostat in favor of calibrated water neck restrictors, is the goal to eliminate potential thermostat failures, as well as preventing conventional thermostats from being forced closed under high rpm water flow. Even though these concerns are genuine, they do in fact make 'racing' thermostats, called "Balanced Thermostats" which eliminate these concerns...




    </TD><TD colSpan=5></TD></TR><TR><TD height=281></TD><TD colSpan=7></TD><TD height=281 vAlign=top width=465 colSpan=16 align=left>[​IMG]</TD><TD colSpan=2></TD><TD colSpan=5></TD></TR><TR><TD height=1></TD><TD colSpan=25></TD><TD colSpan=5></TD></TR><TR><TD height=19></TD><TD colSpan=8></TD><TD height=84 vAlign=top rowSpan=2 width=467 colSpan=16 align=left>
    Standard thermostats can be off as far as 10 to 20 degrees, in regard to their stated opening and closing points. Balanced styles can be as accurate within 2 degrees. Standard types are prone to failure, such as the one in the center. This results from the brass metal bridge over the plunger giving way, therefore closing the thermostat completely, restricting all water flow. Within minutes, total engine destruction is inevitable.




    </TD><TD></TD><TD colSpan=5></TD></TR><TR><TD height=65></TD><TD colSpan=8></TD><TD colSpan=17></TD></TR><TR><TD height=10></TD><TD colSpan=41></TD></TR><TR><TD height=5></TD><TD colSpan=5></TD><TD height=228 vAlign=top rowSpan=2 width=349 colSpan=12 align=left>The balanced version uses a "wax pill" (yellow arrow), which is designed to melt at a predetermined point, thereby opening the thermostat at precisely the same temperature, every time. The 3-port construction (blue arrow) equalizes the water pressure from above the valve (radiator side) to the higher, pump pressure side. This allows the thermostat to open effortlessly and accurately no matter what the water flow, or engine RPM is at that particular time. Non-balanced designs are prone to be forced closed when the water flow abruptly increases, such as during sudden increases in engine RPM.



    Also, note the increased water flow capability (red arrow) of the Balanced model compared to the relatively smaller standard style thermostat.




    </TD><TD colSpan=24></TD></TR><TR><TD height=223></TD><TD colSpan=5></TD><TD></TD><TD height=227 vAlign=top rowSpan=2 width=329 colSpan=16 align=left>[​IMG]</TD><TD colSpan=7></TD></TR><TR><TD height=4></TD><TD colSpan=18></TD><TD colSpan=7></TD></TR><TR><TD height=11></TD><TD colSpan=41></TD></TR><TR><TD height=149></TD><TD colSpan=6></TD><TD height=149 vAlign=top width=688 colSpan=27 align=left>
    Tests have proven that by simply opening the thermostat precisely at the same temperature over and over again, the engine remains cooler on the average. Engines can warm up faster to normal operating temperature, and cool down quicker once the engine exceeds the set point. This results in longer cylinder wear, and consequently longer engine life. By opening the thermostat 'on time', every time, the temperature swing is reduced, allowing for more complete cooling. By getting the thermostat open as quickly and as wide as possible, allows the warm water to exit quickly, thereby getting it to the radiator to begin it's cool down cycle as fast as possible. As a result, getting the cool water into the engine and holding it there, extracts as much heat from the engine as efficiently possible, therefore enabling to radiator to work at it's maximum potential as well.




    As you can see, there's a lot more to a thermostat than just 'making your gauge stop' at a certain point!




    </TD><TD colSpan=8></TD></TR><TR><TD height=9></TD><TD colSpan=41></TD></TR><TR><TD height=4></TD><TD colSpan=13></TD><TD height=299 vAlign=top rowSpan=2 width=512 colSpan=19 align=left>[​IMG]</TD><TD colSpan=9></TD></TR><TR><TD height=295></TD><TD colSpan=4></TD><TD height=297 vAlign=top rowSpan=2 width=171 colSpan=8 align=left>
    The graph to the right illustrates the importance of how critical optimum coolant temperature is to the longevity and performance of an internal combustion engine. Cool water makes good horsepower, to a point. Warm water minimizes engine cylinder wear, to a point also.



    However, there is a "middle ground" where both optimum performance as well as minimal wear share similar characteristics. That "magic" number lies in the 175-180 degree range, which requires a 180 degree thermostat..




    </TD><TD></TD><TD colSpan=9></TD></TR><TR><TD height=2></TD><TD colSpan=4></TD><TD colSpan=29></TD></TR><TR><TD height=157></TD><TD colSpan=4></TD><TD height=157 vAlign=top width=691 colSpan=27 align=left>
    The all too commonly used 160 degree thermostat is way too low to be considered for performance or engine longevity. As the chart illustrates, engine wear increased by double at 160, than at 185 degrees. So then, why do the 160's exist in the first place? The 160's were commonly used in older, open loop cooling systems where only 6 pound radiator caps were used, and low 212 degree boiling points were experienced. In contrast, modern cooling systems can see upwards of 260 degrees in coolant temperature with radiator pressures exceeding 45 pounds. Many early hot rodders found the 160's to be better performing than the 190's, however, the in between "180" appears to satisfy both ends of the spectrum. The correct water temperature is required for the cylinders to achieve a minimum specific temperature in order to allow a fully homogenized Air/Fuel mixture to combust efficiently. Guess what the minimum number is&#8230; right! 180 degrees. Even so, you might see some still recommending the lower 160's, for no other reason than to possibly get that last drop of horsepower out, at the high price of dramatically reducing the life of the engine and it's internal components.





    Here is the link which also offers the Mr. Gasket high-flow balanced thermostat, I mentioned in my previous posts:
    http://performanceunlimited.com/cobravalley_drivetrain/thermostat.html
    </TD><TD colSpan=10></TD></TR></TBODY></TABLE>​
     
  30. Bored Over
    Joined: Aug 9, 2008
    Posts: 74

    Bored Over
    Member

    Hey Miller, you wouldn't be refering to a post on a certain Olds forum would you? I would post a link, but I don't know how.
     

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