why run a thermostat??

Ok this may be a stupid question, but I was thinking why use a thermostat on the buick in my T. In a hot rod in California that will probly never be driven in weather colder than maybe 85 degrees, wouldent you get better flow and therefore better cooling in a car that you dont have to worry about warming up. or am I missing something??

 

you gotta slow the water down, or it will not cool properly and you will overheat.

it's science man.

- Joe

 

If you have a well designed system, matched for the horsepower and efficiency of your engine you will need a thermostat. Running too cold can be a major problem, combustion is not as efficient at lower temps and the metals used can be more brittle and prone to breakage.

Plus getting the engine up to temp helps steam off any condensation build up in the crank case.

 

What he said.

 

No, you are not missing anything, if you read a little more and learn what a thermostat does. Search the issue, facts will set you free. Then, if you choose not to run one, you won't be missing the point, you'll be ignoring it..........................

 

The purpose of a thermostat is to keep the water in the radiator long enough to cool it. Without a thermostat all you are doing is circulating hot water.

 

I wouldent run without one without understanding why its there, thats why im asking. so too much flow is bad, and running too cool isnt good also. thanks, that was quick.

 

I went to college to be a auto mechanic and was told by one of the instructors that if you didn't use a thermostat, the front of the engine would run cooler than the back and the cylinders in the front would wear faster. Never became a mechanic and don't know for sure if that is true. If everything is working correctly you will not overheat using a stat.

 

Thermostats are designed to keep the water in the radiator longer for cooling summer or block for heating winter. and give you a all around controlled temp. And should be used for both purposes...John

 

so what thermastat temp. would be suggested for a hot rod drivin say between 85 to 105 degrees? or are there many other factors such as radiator, water pump, ect...

 

Actually, you can. I run a water restrictor in my drag car, keeps it a spot on 180 & I can cool it to stone cold & not block water in the block. Problem with it on a street car is it takes longer to get up to temp & you have to trial & error it to get it right. I never run a street car without one

 

G-zillions of engines use them. But you probably don't need one... until you realize you do after all. No sense reinventing the wheel, eh? Gary

 

Here in warm SoCal, i DON'T run them. My cars warm up quick enough without em. I just don't trust them not to stick. And the fucking things only stick CLOSED.

WRONG. But if you really believe you need to slow the water down to cool, then cut the guts out of the 'stat, and run what's left.

 

Not so. The purpose of the 'stat...........it brings the engine quickly to it's most efficient operating temp. Especially important in COLD climates (heater and defroster use). The water can only flow so fast through those thin radiator tubes. If the water flows 2 times faster, it cools half as much but twice instead of once. So, it's a "push" if the water flows fast Vs. slow. It's been proven. In my MANY years as a mechanic, I've NEVER had the addition of a 'stat cure a hot running car, NEVER. I've heard people claim this, but it's NEVER been a hands on experience of mine

 

good point, also if that was true a high flow water pump would be less efficiant. Groucho, do you use a restrictor plate or just the water outlet to the manifold? how is it at warm-ups on average spring or summer day? how long have you run without? thanks

 

1. Different metals (i.e. aluminum pistons, cast iron cylinders, tri metal bearings) have different expansion and contraction rates at different temperatures. Running at a consitent temperature runs the moving parts at a consitent gap. An engine goes through more wear warming up than it will runing warm through the next tank full of gasoline.
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2. The by-pass gasses (Crankcase gases that are passed by the piston rings) can collect in the oil and dilute it. This mostly consists of water vapor from the cumbustion process, exhaust constiuents (particulates and burned oil) and lighter end gasoline vapors. A higer temperature allows the water vapor light ends of the gasoline to escape your heavy end motor oil. The particulates are handled by the oil filter but the smaller stuff eventually will turn your oil black.
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3. Sorry, but the coolant "flowing too fast" is a myth. The thermostats job is NOT to slow down the coolant so that it can cool better. Basic thermodynamics would have us know that the heat transfer is greater when the temerature delta is greatest (i.e. the more there is a temperature difference, the greater rate the heat can be transfered between the two surfaces). I am sure that there will be many stories of how this is not true, but you should probably argue with the engineers that designed your engine if you don't believe it. Why would you own an engine designed by engineers that you don't believe anyway?
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4. Higher pressures (i.e. higher pressure caps) raise the boiling point for a liquid (i.e. if you cap is loose the coolant/water mix will boil more quickly). Too high of a pressure can cause damage to the radiator, or any other weak point in your cooling system (i.e. gaskets, freeze plugs). Maybe this is where some of the "myth" of point 3 above comes from.
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5. Running without a thermostat does not make the engine produce any less heat that needs to be transfered away (to the coolant). If you have a engine overheating issue, then removing the thermostat will only buy you a couple of minutes more than running with a thermostat (because the coolant is not reciculated in the block until the thermostat opens). This works for a dragster running the quarter mile, but not much more.
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6. Modern engines run 185F or higher to help stabilize the combustion temperature so they can properly predict the air/fuel ratio and EGR amounts for proper emissions tuning.
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7. Another myth, 100% coolant cools better than a 50/50 mix. Actually the reaction of the glycol with the water is the best balance for heat transfer and corosion of internal parts (i.e. build up of rust and corosion).
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Recommendation: The engineers who designed your engine probably did the homework to determine the proper thermostat and pressure for your engine and cooling system. Why would engineers add cost and complexity to the cooling system to decrease cooling system performance (i.e. add a thermostat)? If you think you can "hop-up" a cooling system by removing the thermostat, there is nothing I can say that will convince you otherwise.

Most of all, have fun!

 

Run one and fuggetaboutit. If you are needing to run a car without one, you have other problems with your cooling system you need to address.

 

I dont have any problems or anything, the car isnt running yet, I was just thinking about it and I am like the kid with a million questions. but hey thats how you learn right.

 

I've heard people say it's to slow the water down or it won't cool the engine, but I think that's an old wives tale and not true. It's basically to allow the engine to get warm enough, and to stop it from cooling off too fast. If you have no thermostate, some engines may never get up to temperature, and if you are up to temperature, and you go down a steep hill without a thermostate, it may cool off too fast and crack the block.

 

If the engine and coolant are at the same stable temperature and the water pump and fan stops (i.e. the engine is off), then the thermostat will not make any difference (open or closed there is no flow). The whole thing cools down at whatever rate the transfer of heat can occuer between the surfaces.

 

I've used restrictors, and found no advantage. I've been running no 'stats for YEARS. If I lived in a really cold climate, I'd use them to get the heater working quicker. Here, in SoCal, no issues. As a mechanic, I do believe in the theory of the 'stat. But, in an ex girlfriend's car, I got THREE sticking 'stats in a row, and almost "cooked" her motor. Which I would've had to fix for FREE

 

I want my cars to run between 180 and 200 to extend the life of the engine and for fuel economy. Lots of folk lore about slowing down the coolant in the radiator but in my real life experience it can be hard to get the temp up to optimal efficiency with out one. I think it comes from the often repeated flathead lore. Yes I run stats in my flathead and no it never overheats. My 34 P/U with the Stude V8 in it running behind a stock 34 Ford radiator wouldn't get above 140 in the spring time and took forever to get there with air temps in the 70s. A 160* stat solved that problem. Thermostats are made to maintain a minimum temperature and get the engine to that minimum quickly. Not all folklore is accurate.

 

Ain't that the truth...

 

Actually, I do not know how you can get the coolant to cool off too fast to crack the block (maybe a fire extiguisher on the radiator)? I suppose you could hit the block with some cold liquid when the engine is hot and that could crack it (i.e. maybe while doing the "Gunk" spray on engine rinse cycle), and I have never seen it, but I suppose if you cooled one section of the block much faster than the others a crack is possible.

 

i ran a car without one for a while obviously only was good in the summer lol.. i was young and dumb and didnt know they were cheap, just knew mine was stuck.. 6 months later after a few months of winter a buddy laughed his ass off and we went and bought the $3 thing on his dime, i bought the $1 gasket LMAO..

anyways, on a more related note i ran no thermostat in my olds in my 31 cause it ran a lil warm, it did help a bit to not have it in there.. and ive been thinkin bout takin the one outta my 289 just for fucks sake, the cars only get summer lovin anyways, like that chick from grease

 

This is the best reason I have read as to why you would not run a thermostat. With all of the thermostats that do work on the road, that is a incredible coincidense! Is there a POS thermostat maker we need to stay away from?

 

It's gonna be trial and error, or you might get lucky on your first try. But It's a hot rod and no owners manual. So I would say either 180 degree or 195 degree. Prolly the 180 degree I would try first...John

 

Sounds good

 

i have removed thermostats because they stuck, the engines then ran to cold, put a new one in and they were fine for as long as i owned the car, in the last 35 years of messing with cars i have only had one stick and heard of one other, as a side note i like to drill a couple 1/8" holes in the outer ring of stats, just to let the air out so i dont have to wait for the start to open on a new engine.

 

I used to use nothing but Stant thermostats for years. Back when I worked in radiator shops as a kid, that's all we would install. About five years ago I had the same run of bad luck Groucho has had , and looked elsewhere. What I found is Miloden racing thermostats. I get them locally from Lopars, Jegs and Summit have them too. They started stocking Mr. Gasket thermostats a while back, claiming they were from the same source, but I had problems with them right away. Went back to miloden, Problems solved.