Help settle a thermostat bet

[imnezrider]

So, a friend and I have this bet about thermostats. He says if you run a "cooler" stat (160 degree), your engine will not get as hot as it would with a 180 degree. My contention is that, assuming a 100 degree day, once the stat is open, the engine temp will rise to it's "normal" operating temp regardless of the "lower rated" thermostat and would not run "cooler". What say you?

 

[kelseydum]

According to this I got from another site...

"Any liquid-cooled car engine has a small device called the thermostat that sits between the engine and the radiator. The thermostat in most cars is about 2 inches (5 cm) in diameter. Its job is to block the flow of coolant to the radiator until the engine has warmed up. When the engine is cold, no coolant flows through the engine. Once the engine reaches its operating temperature (generally about 200 degrees F, 95 degrees C), the thermostat opens."

I would not think the engine would run cooler. The thermostat opens when the engine reaches operating temperature. Not every engine runs the exact same temp. The cooler thermostat would just start cooling sooner not better. I'm no expert so correct me if I'm wrong.

 

[Gastrick]

The degree rating on a thermostat is merely the temperature at which it opens, allowing coolant to flow through the system. Ultimately, the coolant should reach the same operating temperature no matter when the thermostat opened. There are instances of engines running too cool, necessitating the use of a thermostat with higher temperature rating.

 

[imnezrider]

Thanks guys...I'm looking forward to my free dinner.

 

[Gregster]

don't go cheap ! if it's free make sure you order shrimp cocktail !

 

[Sam_Fear]

So will a motor without a thermostat operate at the correct temperature all the time?

Seems to me you need a cooling system that is able to over-cool the motor at all times in conjunction with a thermostat to keep the temperature UP to proper range.

 

[bob w]

Sam, Correct-a-mundo!!!

 

[Hollywood Eddie]

The Tstat is there to bring the engine optinum running temp. To allow all the sensors/carb/Efi to produce the best performance. To give us the creature comfort of heating.

 

[Sam_Fear]

Sam, Correct-a-mundo!!!

Wow. Usually when I spout stuff off like that I'm dead wrong.

Uh oh. That means he's buyin dinner.

 

[Gastrick]

Without a t-stat at all, coolant can flow through the system too rapidly, not allowing the coolant to stay in the radiator long enough to cool the liquid. Based on his original question (160 vs 180), I still maintain that he is the "most" correct. I may be thick headed though [S

 

[donsrods]

Actually, in my case the higher temp thermostat did raise the overall temp. My T runs cold, and with a 160 thermostat it won't get over 150 going down the road. To cure some incomplete combustion I was getting I put in a 190 degree one, now the temp is up to 170 going down the road. The problem I have is that my radiator is just too efficient. I can actually hold my hand on the bottom hose and it is only very luke warm.

The car now runs better since it is getting hotter.

Don

 

[Gastrick]

There are instances of engines running too cool, necessitating the use of a thermostat with higher temperature rating.

That's what I was saying here Don.

 

[gassersgarage]

My '51, without a thermostat, ran at 215. I put a 160 thermostat in it and it now runs at 185. I also got a thermostat with by-pass holes in case it ever sticks.

 

[Willowbilly3]

I think your friend is more right than you are. You can prove (or disprove) the arguement by installing a good temp guage and try different thermostats. You should notice that the cooler stat will be cooler on the guage. I suppose there might be extenuating circumstances that it wouldn't but I am talking about a basically street driven car, not a top fueler.

 

[BigIrish]

I think he is correct, only assuming the cooling system is up to the job of cooling it down to 160. If it can't keep up with the load for whatever reason, it's not going to make a diff what temp the thermostat is - it's going to run hotter than you want it. That said, if you have a proper-functioning system, with extra capacity, that will work.

I've heard several people claim a lower temp thermostat is a cure for a shot cooling system that is overheating, but that's not the case.

 

[Sam_Fear]

So, a friend and I have this bet about thermostats. He says if you run a "cooler" stat (160 degree), your engine will not get as hot as it would with a 180 degree. My contention is that, assuming a 100 degree day, once the stat is open, the engine temp will rise to it's "normal" operating temp regardless of the "lower rated" thermostat and would not run "cooler". What say you?

'once the stat is open, the engine temp will rise to it's "normal" operating temp regardless of the "lower rated" thermostat and would not run "cooler". '

I re-read the question, and this part is problematic. "Normal Operating Temp" should be set by the thermostat, not the radiator. Otherwise your running above "NOT". If the "NOT" is 190 degrees no matter 160 or 180 thermostat, I want a better radiator.

What happens when you get into a abnormal operating situation? Like stuck behind a bus dumping heat at you in a 10mph jam... potential overheat.

 

[imnezrider]

'once the stat is open, the engine temp will rise to it's "normal" operating temp regardless of the "lower rated" thermostat and would not run "cooler". '

"Normal Operating Temp" should be set by the thermostat, not the radiator.

Thanks for that input, but make sure I understand what you are saying. In other words, if a car runs at 180 degrees with a 180 thermo, then it would run cooler with a 160? I can't follow that theory. Sorry, I'm dense on the subject.

 

[bowatjr6969]

I may be way out of line with this !!!! But it would seem to me that if you ran a 160 degree thermostat and your cooling system ran normal at 180 degrees the 160 degree stat would almost always be in the open position causing your coolant to flow too quickly through the radiator.

I will by the comment that if you have a really good radiator then your system will run with whatever temp stat you install. But I would almost bet in most cases that guys look past the cooling of a motor with the sense of I need a radiator!! If you plan correctly I guess it would run cooler at a lower temp stat. But if you just build a car and install parts you probably have a system that will run a little on the hot side.

Just my .02 cents which may be converted to the yen if my post is wrong!!!LOL[S

 

[R Pope]

Water can NOT pass through a rad too fast to cool it! The same area will release the same amount of heat, regardless of the circulating speed. It is possible that the water can go through the engine too fast to pick up the maximum heat, but even this is unlikely.
If a thermostat causes the engine to run cooler, you may have a pump cavitation problem, or a collapsing suction hose.

 

[Willowbilly3]

Water can NOT pass through a rad too fast to cool it! The same area will release the same amount of heat, regardless of the circulating speed. It is possible that the water can go through the engine too fast to pick up the maximum heat, but even this is unlikely.
If a thermostat causes the engine to run cooler, you may have a pump cavitation problem, or a collapsing suction hose.

I'm not sure of all the physics involved but an engine without a thermostat will often overheat. Whether it's from cavitation, going too fast through the radiator or the engine would be an arguement but the problem and the fix is the same, which ever way you wish to describe it, IMO. In roundy round cars you could not run without some restriction. We had several different discs with different sized holes we used in place of a T-stat. Usually a hole about 3/8"-1/2" did the trick. Plus changing the pulleys to slow the waterpump speed down.
Also my opinion, but a street engine should run as hot as you can. The hotter you run an engine the more efficient it is. Also an engine needs to be hot to burn off the condensation that accumulates in the oil. You will get sludge buildup from running too cool.
I have ran 205 thermostats, summer and winter, with no problem.
With a 12# pressure cap, you wouldn't loose coolant until 238 degrees.