Is my thermostat broken?
#1
Is my thermostat broken?
Pulled LHS thermostat while draining the coolant. It is 180F (says on it)
Did the boiling water test. I boiled the water but i did not observe any changes.
Here is how the thermostat looked like after boiling, which is the same as before boiling.
Is it currently in the closed position? And the fact that it did not "open" during boiling means it needs to go? Right?
Did the boiling water test. I boiled the water but i did not observe any changes.
Here is how the thermostat looked like after boiling, which is the same as before boiling.
Is it currently in the closed position? And the fact that it did not "open" during boiling means it needs to go? Right?
#2
That you observed no movement of the mechanism condemns the unit, yes.
I'm not sure if it's open or closed. A view from the top, through the opening where your string is attached, would be better.
I am wondering of it is physically broken. I *think* the parts have separated. See the section with the squared-off notches? I think the piece directly below those notches should be attached to it. Not sure. But, in any case, the thermostat needs replacing. I replace both. Get the correct ones. Some are not correct for a V12 even though the catalogs say otherwise. Several threads on the subject
Cheers
DD
I'm not sure if it's open or closed. A view from the top, through the opening where your string is attached, would be better.
I am wondering of it is physically broken. I *think* the parts have separated. See the section with the squared-off notches? I think the piece directly below those notches should be attached to it. Not sure. But, in any case, the thermostat needs replacing. I replace both. Get the correct ones. Some are not correct for a V12 even though the catalogs say otherwise. Several threads on the subject
Cheers
DD
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v1rok (07-22-2017)
#3
#5
It is not so much how large the opening is, as the water is forced through it by the ater pump. More so that the rear disc covers the bypass hole inside the thermostat housing. If it does NOT block off the rear opening, then your cooling system isn't functioning correctly. Meaning the some of the hot water gets circulated around the engine again and again instead of it ALL going through the radiator.
#6
I've never measured but I'd say that fully opened vs fully closed amounts to about .375" of travel, maybe a bit more.
Cheers
DD
#7
Let's say the thermostat opens 50% and remains stuck in that position. You'd then have a smaller opening for the coolant to travel thru and less coolant reaching the radiator, despite the water pump's effort at pushing the coolant through the system. The engine might overheat.
More so that the rear disc covers the bypass hole inside the thermostat housing. If it does NOT block off the rear opening, then your cooling system isn't functioning correctly. Meaning the some of the hot water gets circulated around the engine again and again instead of it ALL going through the radiator.
Cheers
DD
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#8
#9
Stats open approx 8mm, or approx 25% of the diameter of the bore.
You need at LEAST 41mm when wide open, and 43mm is preferred, coz stats do NOT work at wide open, they constantly move as engine temps alter.
180 or whatever is the "crack" temp, whish means that's when the stat actually cracks the seat, and is wide open 12degC above that.
This I wrote a looooong time ago.
V12 thermostat fiasco explained.pdf
You need at LEAST 41mm when wide open, and 43mm is preferred, coz stats do NOT work at wide open, they constantly move as engine temps alter.
180 or whatever is the "crack" temp, whish means that's when the stat actually cracks the seat, and is wide open 12degC above that.
This I wrote a looooong time ago.
V12 thermostat fiasco explained.pdf
Last edited by Grant Francis; 07-23-2017 at 10:18 PM.
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v1rok (07-24-2017)
#10
In case somebody is interested, here is how insides of t-stat housing look like. (I put the camera right against the opening)
By the way, what do people normally use as a sealant when installing a new gasket? I have a sealant for oil gaskets. Will it work for t-stat gasket, too? Or because t-stat comes in contact with coolant an not oil, a different type of sealant is needed?
By the way, what do people normally use as a sealant when installing a new gasket? I have a sealant for oil gaskets. Will it work for t-stat gasket, too? Or because t-stat comes in contact with coolant an not oil, a different type of sealant is needed?
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Grant Francis (07-23-2017)
#12
Sorry, What kind of "coating of something" you applied? Does it matter? Or it can be any sealant? (Including oil gasket sealant?)
#13
The coating was on the steel core of the gasket. Factory applied to make a complete gasket. You don't have to do anything, just use them right out of the bag.
#14
Another question about thermostats.
Kirby's book recommends to drill a small 1/8" hole in the flange if an aftermarket thermostat comes without a jiggle pin.
I got Stant super duty t-stats.
Do they have jiggle pins?
If not, where exactly is this small 1/8" hole supposed to be drilled? Does anybody have a picture of the hole?
Kirby's book recommends to drill a small 1/8" hole in the flange if an aftermarket thermostat comes without a jiggle pin.
I got Stant super duty t-stats.
Do they have jiggle pins?
If not, where exactly is this small 1/8" hole supposed to be drilled? Does anybody have a picture of the hole?
#18
#20
As stated here thousands of times.
If ya dont get the air out of a V12 and allow a passage for it at all times, it WILL overheat, and ruin your bank balance.
That hole, jiggle pun, whatever at 12 o'clock is coz air is at the top of any area, usually, and it will simply slide thru that hole, out via the not so simple air bleed system, and allow proper operation of the stat. Air behind the stat, in enough volume, will prevent the stat from opening, as it only works in liguid.
Also, air pockets that become steam pockets, are very destructive. The V12 does get these pockets around #5 & 6 cylinders on both sides if bleeding is not done properly, and the air bleed system is not maintained.
If ya dont get the air out of a V12 and allow a passage for it at all times, it WILL overheat, and ruin your bank balance.
That hole, jiggle pun, whatever at 12 o'clock is coz air is at the top of any area, usually, and it will simply slide thru that hole, out via the not so simple air bleed system, and allow proper operation of the stat. Air behind the stat, in enough volume, will prevent the stat from opening, as it only works in liguid.
Also, air pockets that become steam pockets, are very destructive. The V12 does get these pockets around #5 & 6 cylinders on both sides if bleeding is not done properly, and the air bleed system is not maintained.
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v1rok (07-29-2017)