Thermostat Question

[sodbuster]

OK all you motor heads ..... for the rad. thermostat, the little hole in it with the little valve thingy majobber .... should that go to the top or bottom AND why ??

This isn't a contest but clarification for ShopTalk.

Thanks in advance for your input .......

[Whiskerfish]

http://www.ngwclub.com/forum/viewtopic. ... rientation

[sodbuster]

WF-
I seen that post but I also found other posts saying just the opposite .......

[Whiskerfish]

That picture is out of the HSM.

[sodbuster]

Those pics don't reference anything about the vent hole .....



The vent was to the top when I took it out but when I referenced several postings I got conflicting feedback as to it's correct orientation.

I'm inclined to put the thermostat back the same way as the bike ran fine that way but I'd rather know the correct way before I do.

[puffy75]

I am not sure about the conflicting info... but I think the thermostat will only fit the way the manual shows in these diagrams WF has provided. The vent can be at any point in the housing.

[zane]

I don't have the answer to your question, but having just replaced my thermostat, I do know this much....

..... the new, Honda thermostat I installed did (does) not have that little
valve hole.

..... the thermostat I removed for replacement did not have the little vent
hole.

..... I have two other engines that I use for parts. I removed the
thermostats from them. Both of them were like the one you have
pictured, and had the vent hole placed at the top.


I'd be really quite surprised if that vent hole/valve was supposed to be placed at 6 o'clock rather than 12 o'clock.

(I've been wrong before though - plenty!)


Cheers,

Zane

[Patrick M]

If it truly is a vent hole, then what it would vent would be coolant in a gaseous state, I am thinking. That could only be accomplished by having the hole in the top position; or so it would seem.

[sodbuster]

I am not sure about the conflicting info... but I think the thermostat will only fit the way the manual shows in these diagrams WF has provided. The vent can be at any point in the housing.

The conflicting info is from reading several posts when I did a search and found where some said to have it pointing up and other posts said to have it pointing down. My belief is that it's to allow any trapped air to escape and be pointing up.

Also, the thermostat I bought to replace it is the same way.
NAPA #101, same as what is posted all over this site as well as other Goldwing forums

[sunnbobb]

Conversely, my thinking is it goes down. Purpose being to allow a small amount of flow to clean the bottom of the housing...

[cycleman]

Vent whole has to be at the top to let air bubbles bleed out of the motor and into the rad and then into overflow.

If you don't believe this then put some water in a clear tub & see where the bubbles collect. They always collect on the top. Air is lighter than water. If you put the vent hole in the bottom air can't escape.

You can answer search and get many different answers but generally speaking there is only one right way and it may not always agree with what you or I think but that's life.

[dan filipi]

Looking at the cooling system in a mechanical fashion tells me the orientation of that hole does not matter.
Why I think this is because there is a high rate of flow and pressure within the cooling system particularly behind the Tstat. Any minute amount of air so called "trapped" behind the thermostat will get forced thru simply by the flow and pressures that a tiny hole positioned at the top will make no difference.

[sunnbobb]

my thought too Dan.

[sodbuster]

Looking at the cooling system in a mechanical fashion tells me the orientation of that hole does not matter.
Why I think this is because there is a high rate of flow and pressure within the cooling system particularly behind the Tstat. Any minute amount of air so called "trapped" behind the thermostat will get forced thru simply by the flow and pressures that a tiny hole positioned at the top will make no difference.

I would tend to agree with that except when doing a flush of the system you are going to have that initial air pocket you want to get rid of that may be on the stubborn side...........

[Old Fogey]

Looking at the cooling system in a mechanical fashion tells me the orientation of that hole does not matter.
Why I think this is because there is a high rate of flow and pressure within the cooling system particularly behind the Tstat. Any minute amount of air so called "trapped" behind the thermostat will get forced thru simply by the flow and pressures that a tiny hole positioned at the top will make no difference.

Dan, if that was so, there wouldn't be any need for a vent hole at all. If you examine the pin it has a taper on the back of the head so that it plugs the hole.
I reckon, when there is pressure on the back of the thermostat, that the pin is forced into in the hole and blocks it.
I think Sodbuster and Cycleman have it about right, hole at the top to allow filling of the system when cold and the thermostat is shut tight.