How exactly does this S60 thermostat work??

put it in boiling water and what it work the bottom tube part opens up the spring is there to pull it together

 

cat thermostats are the same thing.

i've wondered that myself.

 

They work because the water flows thru the sides, not top to bottom like a car thermostates..
If you pull the housing off and look how the water flows thru it, you'll see it has to flow thru the sides which is closed in your picture.
But even with it closed there is a port to allow small percentage thru even while cold.

 

The thermostats work because of the difference in resistance of the flowing coolant when the thermostat is closed the coolant goes threw the bypass tube to the water pump, when the thermostat partially opens, there is less resistance for the coolant to go threw the radiator than threw the bypass so some coolant will go to the rad the more the thermostat opens the more coolant goes threw the radiator, when it is fully open the bottom of the thermostat sits on the ring in the housing deflecting about 95% of the coolant threw the radiator.
The thermostat seals are very important they allow the set up to work properly if they are worn coolant will bypass to the rad at any temperature.
Licenced HD mechanic since 1973!

 

if the seals are worn & coolant does bypass the rad, what affect will this have? I have never replaced my seals, but have replaced thermostats.

 

From a cold engine, you should be able to run the engine to thermostat opening temp before the top rad pipe gets any temp in it.
If from cold you get temperature at the top pipe the seals or the thermostats are defective. The engine runs cooler longer burning more fuel.
When the engine is at full temp and the thermostats are fully open it also alows coolant to bypass the rad. That cuts down on the systems ability to cool itself efficiently

 

I am glad I asked. my truck from first start 35-40 outside temp it takes 1 hour for water temp to get to 150. when at operating temp, driving, temp climbs fast & drops very slow. pulling a slight grade 1 mile long in 45 degrees temp get to 210 quick & takes 5-7 miles of down hill driving to cool back to 190. may be I need seals. had everything else done. I had no idea the seals would have that affect. my neighbor, years ago could not get his temp up in the winter. idleing it would not even register on dash gauge & that one night, it dumped so much fuel in the oil the reading showed over 2 gal over full on dipstick. I would guess the seals might be cause of running cold longer, but did not think it would run temp hotter too. never knew anything about bypass hose, just thought it was like a car. top hose, bottom hose, thermostat, rad, water pump.

 

I would have to tilt the cab to check top rad hose, so not as easy. the seals.. they are the metal rings that go into the thermostat housing correct ?