Thanks BigSix, that's exactly what I was trying to explain.

If the engine relied on the radiator to regulate the temperature, there will be no room for increased heat output and the engine will eventually overheat as the system temperature rises to equilibrium. The radiator should be able to reject a lot more heat than what the engine is producing (especially on an unloaded vehicle), otherwise it will overheat.

The amount of heat into the coolant from the engine depends on the work being done by the engine, the water flow rate, and the temperature delta between the metal and the water. The amount of heat rejected by the radiator is dependent on water flow rate, air flow rate, and the temperature delta between the coolant and air temperature. A larger temperature delta in either place will allow for more heat to be transferred for the same flow rate - i.e. a 210 degree coolant temperature will reject more heat from the radiator to air at 70 degrees than 180 coolant temp to 100 degree air. Similarly, water flow rate can be varied to alter heat rejection, which is the job of the thermostat. If the radiator is overcooling, the thermostat will close (progressively) until the outlet temperature of the engine reaches the thermostat setpoint. If the radiator is undercooling, the engine will run hotter and hotter until the temperature delta between the air and water temperature gets to the point where it can transfer enough heat.

The rated temperature is the fully open temperature. I know it's a different application, but the motorcycle engine we used for our FSAE car at school listed in the service manual that the 195 degree thermostat started opening at 176 and was fully open at 195 - I expect the same here. If it can't regulate to or very near the rated temperature, then there is something not right with the thermostat or the cooling system.

Not to sound cocky or anything, but thermodynamics was one of my best classes in mechanical engineering.

 

[quote=Jermafenser;8084750]Uh, what? Yes, it does. What's inside a thermostat? A wax pellet.

NO! No more that crap of yours! Seriously, where did you get that mumbo jumbo?? Once the thermostat hits its point, the wax melts thus the thermostat pops open. That's it. No more. No less. IT'S EITHER OPEN OR CLOSED! Like I said before: The sole purpose of the thermostat is to prevent the engine from running too cool.


dude. have you even put one in a pot of water and watched it? it opens little by little as the temp rises. does not matter what temp it is rated at, it does NOT just "pop" open.

 

sorry for opening up a acan of worms guys, just was hoping for a little reassurance on the temp. truck was running. i was happy with the rock steady temp of 210. i thought the t-stat was doing it's job. i put it in a pot of water before install. it stated opening at 195-198 and was fully open around 205-210. this is in a 1996-f-250 460 e4od 4x4. if that helps.

 

Yawn.

Do you know what Wikipedia is? It sure ain't an encyclopedia. It is an user-run site. Meaning, anyone can add content to whatever anyone think is correct. I don't consider Wiki a credible source.

 

Your last few posts in this thread aren't exactly credible either.

 

This is completely wrong.

This is completely wrong as well.

You really need to settle down and watch how you talk to people. Posts filled with capital letters, calling other people's words "crap" and "mumbo jumbo" and flat-out wrong information do very little for your credibility around here.

This is also completely wrong.

One more time... completely wrong.

 

ther⋅mo⋅stat

  /ˈθɜrməˌstæt/ [thur-muh-stat]

–noun

1. a device, including a relay actuated by thermal conduction or convection, that functions to establish and maintain a desired temperature automatically or signals a change in temperature for manual adjustment.


ra⋅di⋅a⋅tor
  /ˈreɪdiˌeɪtər/ [rey-dee-ey-ter]

–noun
3. a device constructed from thin-walled tubes and metal fins, used for cooling circulating water, as in an automobile engine.

 

Huh? How will it overheat? Get real. Unless the water flow or the radiator is not working effectively (assuming the cooling system was properly rationalized), it's impossible for the cooling system to overheat. Why is the lower radiator hose always cooler? The radiator fins cool down the hot water. When it reenters the water pump, it is too cool so the thermostat will close again until its opening point. The flow may change or even restrict, but that's due to the wax always fighting to get back to its natural state. It's hard for the cool water to heat up fast inside a toasty system, hence you won't see the temperature vary wildly when the system see-saw.

Once again, 180 or 195, it will reach 210 regardless. There is no point in installing a cooler thermostat period, especially on newer vehicles with onboard computers.

 

Settle down? Oh, don't be so dramatic. I am merely trying to get my point across using a few techniques. Okay, mother?

I believe you just contradicted yourself. Settle down there!

So far all you're doing is crying "wrong". Why don't you offer your explanation, then? Hm? Or are you frightened for your 'credibility'?

 

This forum is not really meant for arguments and name-calling, it's meant for the informative exchange of information. I'm not going to get in an argument with you over this, you clearly have a chip on your shoulder and I don't wish to be a part of it. Besides, there are far more interesting things to argue about than what a thermostat does or what a radiator does.

I reported this thread to the administrators as I believe it violates the guidelines of the site. Maybe they will be able to convince you to tone it down a notch.

 

You must not have read my last post. It explained how it would overheat. I'm not posting this stuff to argue, but to post correct information for others who may be willing to listen and learn how the system functions. It's obvious you do not know anything about thermodynamics or how heat exchangers work.

I like this contradiction here:
It can't be both at once. If 210 is the thermal equilibrium point, the thermostat will always be open.

Please stop trolling.

 

Dude...chill out....NOW...try being nice

... just because you have an opinion does not mean it is correct or the only way.

 

once again guys, sorry for opening up a a can of worms , just was hoping for a little reassurance on the temp that the truck was running. i was happy with the rock steady temp of 210. i thought the t-stat was doing it's job. I'm just used to other vehicles i've had running at 200 deg. i put it in a pot of water before install. it started opening at 195-198 and was fully open around 205-210. this is in a 1996-f-250 460 e4od 4x4. if that helps.

 

No need to be sorry...we just need some to be ....or have civility
This is about helping others...after all that is what forums are about

 

^^^ What he said.

Don't worry, you did nothing wrong. I did not know there was such passion in the thermostat and radiator subculture.