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Discussion Starter #1
I'm wondering if anyone has taken the thermostat out permanently and what where the results? Did it have any affect in lowering the normal running temps? What temp range did the bike run with the thermostat removed?

Although the thermostat opens at 143F the bike runs in the 180F-204F range in normal ambient temperatures. An indication the cooling system is marginal at best and probably the temperatures are to satisfy the EPA. In the winter my bike runs around 160F so I don't see why not let it run in that temp range all the time. Off the top of my head I don't see any detrimental issues in letting the bike run cooler other then burn a little more gas.
 

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Never a good idea on modern engines. I guess if you never ride in cold weather, maybe you could get away with it. I ride in temps as low as freezing (that's my personal limit.) That cold, the engine will never get to operating temperature. This can lead to not only excessive fuel use, but things like early fouling of plugs and thinned oil from unburned fuel washing past the rings. Keep in mind this comes from working with cars, but I see no reason that the same would apply to our bikes.
 

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The cooling system is a supplemental part of the over all package. It is not designed to be like your car, just to help with the cylinder head cooling. I would leave it in since I'm sure the computer has some sensors to control motor function per cooling temp. When I had my 900 with no cooling gauge nothing ever bothered me about cooling system temperature. So now as long as it is not in the red zone I just ride.
 

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Cooling systems work surprisingly well. Think: "never quite warmed up". I had an old Chevy when I was young and dumb. I took the thermostat out of that, and it never even got warm enough to register on the temp gauge. I would also imagine that the thermostat "begins" to open at 143*, but 200* is what just about every other gasoline engine on this green earth is designed to run at. Its the perfect line between hot enough for the fuel to burn efficiently, and not so hot that the engine begins to melt. If it runs cooler, the cooling fins on the engine itself are doing their job too well.
 

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Discussion Starter #5
Comparing car cooling system to the Voyager is apple an oranges. Until somebody takes the thermostat out and publishes the results none of us can say with certainty what the results would be. That's why I'm asking.

Thanks for the replies.
 

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Back in the old days you could take the thermostat out and it would run cooler but now days they use thinner and smaller radiators and the thermostat slows the coolant down where it can let the coolant cool down . Taking it out you may take a chance on overheating your bike because the coolant travels thru your system to fast and cause overheating and if you do not have a gauge you could melt down your engine .
 

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Discussion Starter #7
Increasing coolant circulation will cause the engine to overheat is preposterous.

Gent's we can't see the forest for the trees here. A few givens:
1. With no air flow over the radiator this bike will overheat even with the thermostat removed.
2. At speed with air flow over the radiator the engine will run cooler if I remove the thermostat.
3. By controlling the air over the radiator it is possible to make it run any temp between steps 1&2 with simple piece of cardboard.
4. Making the engine run hotter is a lot easier than trying to make it run cooler.

I ride in cold weather also and the bike runs around 160F in the winter. That's the target I would shoot for during the summer by controlling the air flow... and that IS doable. I'd be happy to just lengthen the time the fan kicks in at red lights. Yesterday at 90F it took less than 30 seconds and roasted my inner legs.
 

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I do not believe the radiator is big enough to do what you are asking. You can wire in a fan switch like racnray did to keep temp down in slow traffic or at red lights. The faster the coolant runs through the motor it has less time to absorb the heat from the motor and send it to the radiator, doesn't seem that preposterous to me. Remove your thermostat and report back and let us know how it works for you.
 

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Question - does the coolant temp sensor do anything besides turn on the fan? If so removing the thermostat may cause some serious drivability issues. Certainly a possibilty if the bike has an O2 sensor. Even when open the thermostat reduces the flow since it is not a full port "valve". Without a thermostat it will certainly warm up more slowy. however if it will run cooler or not when warmed up could not say. Even racers that remove thermostats on cars often run a restrictor. According to the manual there is no large bypass for coolant to flow when the thermostat is closed. However there is a bleeder hole. which I assume is in the thermostat. One couls possably drill it out to a larger size. However for street riding would not mess with it. VMax tend to run hot - REAL hot in town when doing what they do best. The remedy to that was replace the cooling fan temp witch with a more accurate lower temp one. Adding water wetter also helped, but that can cause other issues such as foaming.


http://www.vmaxoutlaw.com/merchandise/index.htm

Scroll down a little to see info about the temp switch and water wetter.
 

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Is there a way to change the resistance on the fan relay to turn on sooner? I know my 900 I put in a resistor to correct the fuel gauge, maybe that could be done on the fan. Maybe racnray will add something, maybe this would work without adding a manual switch to turn the fan on. I know he talked about the bike being more comfortable when stuck in traffic with his switch he added.
 

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Comparing car cooling system to the Voyager is apple an oranges.
Well, maybe tangerines and oranges, they're still related functions.

Until somebody takes the thermostat out and publishes the results none of us can say with certainty what the results would be. That's why I'm asking.
I can't disagree with that logic. I have rode my Vaquero in near-100 degree temps in rush-hour traffic, and never had my temp light come on. I was one miserable puppy though! It sounds that you are having more heat issues than I. Anyway, I'm gonna guess that you will likely try this out, and I would certainly be interested in the results!
 

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Discussion Starter #12
Lets get this out of the equation, removing the thermostat will not overheat the engine because of increased coolant flow. With that logic the more you restricted the coolant the cooler the engine will run... AND THAT IS PREPOSTEROUS and tells me you don't understand how a cooling system works.

Without air flow the engine will overheat irregardless thermostat or not. It may take a few minutes from a cold start to warm up but that happens all the time when the ambient temp is low... like the winter... so it's irrelevant with the thermostat removed. There is no O2 sensor in this bike and has nothing to do with the cooling system if it had one. Changing the fan sensor to turn the fan on sooner is out of the question, I'm trying to extend the time the fan kicks in not turning it on earlier and roast my thighs at red lights. Suggesting that tells me you don't understand the system either.

To all you who think the engine will run too cool is really not an issue. I can control temp by controlling airflow over the radiator. It is the COMBINATION of air flow and coolant flow that controls the temperature the engine runs. With increased coolant flow you compensate that by restricting the air flow over the radiator. That will give you control by the amount of air you block... IT'S THAT SIMPLE. It would be the same as installing a smaller radiator because that's what blocking the air flow does. A piece of cardboard in front of the radiator will do the job for testing and trials until you get the right size for the temp your shooting for.

From the engines ECU perspective it doesn't care weather it was the coolant or the airflow that controlled the temperature. Blocking radiators to control engine temp has been done since time began... and it's no different now. If you don't understand that there is nothing I can do to help you.

This is really getting know where and a total waste of time but I did find out a lot of people need a refresher in physics 101 on cooling systems.

Good bye and good luck, I should have known from back experience what to expect here.
 

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1) Teh fan relay is controlled by the ECU and the temp sensor is an input to the ECU as well as the O2 sensor on bikes with one. Most O2 sensors need to be at operating temp before they work so some manufacturers keep the sensor out of the eqation until the engine is warm.

2) If the fan turns on later the air coming over the motor will be hotter - basic physics. Keep the engine from getting ther and the air will be cooler.

3) All lguid cooled engines with water/air heat exchangers (radiatior) share the same phyics. No matter how much water flow you have it needs air flow to remove the heat from the liquid.

5) The 1700 liquid cooling is primarily for the heads, They need both air flow over the radiator and the cylinder cooling fins.

6) I made no claim removing the thermostat would cause oberheating.

7) If you are more concerned your legs getting hot than your enigne so be it.

8) If the air flow is hot on your legs they do make a product to deflect that air.

9) Since I do not feel I am real knowledgeable on the subject did not post right away. When I thought I could add something that was not posted I did. However tried to make it clear some of it was speculation and make of it what you will.

10) I am not the one who asked for help.
 

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Removing the thermostat can make an engine run hotter, in some locations of the engine. Wihout backpressure, a free flowing water column will take the path of least resistance and as such it can leave portions of the cooling jackets without coolant flow. This is fact and has been proven over and over on racing machines. Whether anyone believes it or not, a restrictor plate is run on race engines when the restrictor is removed. We all used tape over the rad. air inlet to bring up temps on cold mornings/days at the track. A fast moving water column will also not absorb engine heat as well as one that is balanced for flow vs. cooler size/area. Liquids move faster in the center of a water flow than that in the area adjacent to stationary objects. Surface friction. That is fluid dynamics 101 for the uninitiated.
 

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Just finished reading several dozens of posts originally covering five pages about this topic on another vehicle performance, with some of these folks obviously very well educated. Not one time was anyone snippy - only took less than two pages here. Engine cooling is an extremely complex subject covering heat transference rates of liquids and multiple types of metals, pressure effects on that, flow rates, radius of bends and effects of cavities in the coolant path, even effects of cavitation. There isn't a simple answer! Real-world results from those that actually tried is that their engines ran hotter after removal. Getting snippy and insulting those that joined the discussion and the forum in general does nothing to help your cause.
 

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Just finished reading several dozens of posts originally covering five pages about this topic on another vehicle performance, with some of these folks obviously very well educated. Not one time was anyone snippy - only took less than two pages here. Engine cooling is an extremely complex subject covering heat transference rates of liquids and multiple types of metals, pressure effects on that, flow rates, radius of bends and effects of cavities in the coolant path, even effects of cavitation. There isn't a simple answer! Real-world results from those that actually tried is that their engines ran hotter after removal. Getting snippy and insulting those that joined the discussion and the forum in general does nothing to help your cause.
Old Bear, in reference to "Real-world results from those that actually tried is that their engines ran hotter after removal", just wondering where you got the data supporting this statement?
 

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I have heard this argument before and it makes no sense to me. If what you are saying is true, then as the thermostat opened up more the engine would get hotter because the coolant would be moving faster. That's just backward to how a thermostat works.

I agree that the downside of removing a thermostat is that the engine might not get up to operating temperature.


I agree with csleaman Caterpillar used to call them "water regulator" after they explained to me how the cooling system worked it all made sence, so now I would never remove a water regulator from an engine

as far as motorcycle engine cooling goes my goldwing is the one bike that can be stuck in traffic and not worry about overheating
 

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Lets get this out of the equation, removing the thermostat will not overheat the engine because of increased coolant flow. With that logic the more you restricted the coolant the cooler the engine will run... AND THAT IS PREPOSTEROUS and tells me you don't understand how a cooling system works.

Without air flow the engine will overheat irregardless thermostat or not. It may take a few minutes from a cold start to warm up but that happens all the time when the ambient temp is low... like the winter... so it's irrelevant with the thermostat removed. There is no O2 sensor in this bike and has nothing to do with the cooling system if it had one. Changing the fan sensor to turn the fan on sooner is out of the question, I'm trying to extend the time the fan kicks in not turning it on earlier and roast my thighs at red lights. Suggesting that tells me you don't understand the system either.

To all you who think the engine will run too cool is really not an issue. I can control temp by controlling airflow over the radiator. It is the COMBINATION of air flow and coolant flow that controls the temperature the engine runs. With increased coolant flow you compensate that by restricting the air flow over the radiator. That will give you control by the amount of air you block... IT'S THAT SIMPLE. It would be the same as installing a smaller radiator because that's what blocking the air flow does. A piece of cardboard in front of the radiator will do the job for testing and trials until you get the right size for the temp your shooting for.

From the engines ECU perspective it doesn't care weather it was the coolant or the airflow that controlled the temperature. Blocking radiators to control engine temp has been done since time began... and it's no different now. If you don't understand that there is nothing I can do to help you.

This is really getting know where and a total waste of time but I did find out a lot of people need a refresher in physics 101 on cooling systems.

Good bye and good luck, I should have known from back experience what to expect here.
It sounds like you knew what you were going to do before you even posted here. So if you aren't interested in heeding others thoughts there's really no need to post a question! Why not just remove it then and let us know your results?

Me, personally, I'd start with other solutions forum members have been doing before modifying the cooling system. Wrapping pipes; namely, has seemed to work for a lot of folks.
 

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Hey Raw,

I'm not wanting to debate cooling system dynamics; but heat issues on my Voyager make me think a little differently on bringing the temps down. (NO you don't have to worry about the engine running too cool!):)

Anyway, when I first got my bike, I had a warm engine tick at idle and the gauge would run just past the last white line.

One thing I noticed is that if I warmed the bike sitting in my driveway (air movement from fan only); the first time the radiator fan come on, it would lower the temperature quickly. It would take a little longer the second time, and after about 4 or 5 cycles it no longer would be capable of cooling the engine enough to turn the fan off.

Once our OIL gets hot, the cooling systems are BARELY capable of controlling engine temps.

If your engine is not running over the last white tick mark, and rider comfort is your primary concern; I would spend the money on the KAMS. IT WORKS!:)
As John said; wrapping your pipes will help too.

If you really are looking to cool your engine, you're gonna have to address your oil temp.:(
Synthetic will help with that; also if you are out of your warranty period you can try a Purolator PL14612. (OH NO, I may have started a filter debate!)
Anyway, it's longer and with more surface area it will help to cool your oil a bit. (disclaimer: the purolator filter is made for a car and may cause your bike to burst into flames)

I would also drain, flush and add water wetter to the coolant.
If I remember correctly you're in Canada??
Going to a lower anti-freeze to water ratio can help too, but you need to be careful not to loose the cold weather protection necessary for your location.

Also, pipes and a fuel controller will let the bike breathe; resulting in less heat.

Scott
 

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Old Bear, in reference to "Real-world results from those that actually tried is that their engines ran hotter after removal", just wondering where you got the data supporting this statement?
Same site where there was pages of quite technical discussions on cooling, some Jeep forum. A few of the members stated that they had removed their thermostats and it resulted in even higher temperatures than before removal. I make no claims either way, was just repeating what others claim to have experienced. I do find the topic very interesting, as it is extremely complex with many variables. Even if I was one that personally had tried it out, I would still be curious to the "why" it happened that way. Knowledge is power! Or sometimes, just entertaining!
 
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