350 small block Chevrolet… I have a 180 degree thermostat in place at the moment. I am considering taking it out. Why should I leave it in place… Why should I take it out… Going down the road on a warm day it will go to 185 degrees with no AC on. With AC on it will go 205-207 degrees. Your thoughts…?
The thermostat just lets the engine get up to operating temp quicker, it has no effect on running temperature when it's higher than the thermostat rating. And 207 is a nice safe temperature to be at...many of us with hot rods in AZ are jealous.
Hell, I’m jealous, and I’m in Seattle where half the time the top’s up and the radiator is a water to water cooling device. My daily drivers show a temp increase with the a/c on, but nothing is boiling over or at dangerous pressure or temperatures levels. You’re good.
Sounds OK to me. Running without a thermostat will not make a motor run cooler if your cooling system is near its capacity, which yours maybe is. You could consider it a restriction but it also controls the rate of flow through the rad. Too much flow and the coolant does not have enough time in the rad to shed heat so reduces efficiency. Too higher concentration of glycol antifreeze will also reduce cooling system efficiency in the summer months.
temps listed by 55 Nomad are within the safe range for a motor. need more information on motor, radiator, etc to comment further. as for thermostat, might try one of the high flow designs from Mr Gasket, etc. provides the proper temp setting and lets water flow better when thermostat is open. don't forget other basics like using proper pressure radiator cap for your motor.
Any 352 Ford engine I had I would take the t-stat out in the spring, it went back in for the winter. It was the "cure" for overheating issues I had with them. YMMV.
Yeah, pull it out, run it for a couple of years like than, then when the overhaul time comes (very short time) and you open up the guts and find all that sludge everywhere and you wonder why, refer back to this thread. Along with the other things mentioned, Tstats keep the temps up, enough to burn off the contaminants that oil contains. Detroit and its engine engineers don't spend millions & millions putting in something that's not needed.
did.... https://www.motortrend.com/how-to/preferred-engine-coolant-flow-rate/ Engine Radiator Coolant-Flow Rate Coolant must be in contact with a surface for heat transfer to occur. Too high a flow rate may result in laminar flow, which disrupts surface heat transfer. Best engine coolant flow rates occur by creating restrictions in the engine block through use of a smaller upper hose. Promote good heat transfer in the radiator by increasing the number and size of radiator tubes.
When I was selling auto parts in the early 90s, GM went from a 192 to a 197 degree thermostat in some models. 207 to 210 operating temp is not a problem, as long as you are not losing coolant from the system. A good overflow/coolant recovery system is mandatory. As said, removing the thermostat is generally a bad idea. To get the operating temp down, you need more air flow or a higher capacity radiator.
I did that research seven years ago. This will save him the trouble of looking: Myths For those that cling tenaciously to myths, I am going to take one last crack at forever dispelling the Granddaddy of them all when it comes to cooling systems. The myth is stated as either: Coolant can be pumped too fast through the engine for it to absorb enough heat, or Coolant can be pumped too fast through the radiator for it to cool properly, or Cooling can be improved by slowing the flow of coolant through the radiator so it cools more completely. NONE of these is true. The simple truth is that higher coolant flow will ALWAYS result in higher heat transfer and improved cooling system performance. The reason the myth is so persistent, is that: a) without knowledge of fluid dynamics and laws of thermal conduction it does make a kind of intuitive sense and b) it is based on a tiny kernel of truth, but that kernel of truth does not explain the overall system behavior and so, interpreted out of context, leads to a completely erroneous conclusion. So, let's start with the tiny nugget of truth. If you had a sealed rad (no flow) full of hot coolant, and subjected that rad to airflow, yes, the longer you left the coolant in the rad, the more it would cool. However, if you were to plot that cooling over time, you would find that the RATE at which the cooling takes place is an exponential curve that decreases with the temperature difference between the hot coolant and the air. Put another way - when the temperature difference (delta-T) between the hot coolant and the airflow is large, heat transfer (cooling) initially takes place very, very quickly (almost instantaneously). But as that happens, and the coolant cools, the delta-T becomes less, and the RATE at which further cooling happens gets less and less until the point where the coolant and air are almost the same temperature and continued cooling takes a very long time. This is Newton's law of cooling. To illustrate this, recall my "quenching steel in a bucket" analogy. A good example of this law can be seen when quenching a red-hot piece of steel in a bucket of water. At first, the temperature difference (delta-T) between the red-hot steel and the water is huge - therefore the initial heat transfer occurs at a great rate - the steel initially cools very fast - almost instantaneously. However, after this initial cooling, the delta-T is much smaller, so the remaining cooling occurs much more slowly. If you removed the steel after a second or two - it has cooled a lot - but it will still be warm. To continue cooling the steel to the temp. of the water, you have to leave it in there quite a bit longer - because as it cools - the rate of cooling continually decreases as well. In short - initial cooling is fast, but subsequent cooling occurs more and more slowly until cooling that last little bit takes a long time. So what does this mean? Basically it means, the longer the coolant stays in the rad, the less efficient the cooling that takes place is - to the point that the rate of cooling is so slow as to be detrimental to overall system cooling. Better to dump the big load of heat right away and go back quickly for another load than hang about waiting for a last little bit of insignificant cooling to happen.
According to stats published by Summit the cyl wall wear for a 160 is 3X higher than with a 180-195. No telling how much more w/o one...
Yep, the longer an engine takes to get up to operating temperature, the more damage done. How and why thermostats work are very often misunderstood.
A major problem with this is that the exact opposite is true; laminar flow is the norm for low velocities and turbulent flow results from increased flow rates. Turbulent flow increases the rate of heat transfer. https://en.wikipedia.org/wiki/Reynolds_number https://www.mit.edu/course/1/1.061/www/dream/SEVEN/SEVENTHEORY.PDF Or here, this one may make it easier: https://www.sciencedirect.com/topics/engineering/reynolds-number "As the liquid flow rate is increased, the velocity increases and the flow will change from laminar flow to turbulent flow " Besides, @Ebbsspeed provided the correct answer above; it is all about the delta-t; the greater the delta-t, the greater the rate of heat transfer. And one more bit of logic, if the water remains in the radiator longer, shedding heat, than it also remains in the engine longer, picking up heat. That offsets any increase in temperature decrease that a longer residence time int he radiator may provide.
They are called the laws of physics for a reason. If they were not they would be called the suggestions of physics.
For the sake of not arguing, talk to the guys who do circle track and such, ask them why they run a restrictor plate. Ask them what happens if they ran nothing at all. Those engines are living in to 5-7k range so one would assume the water pump is pushing as much flow as is possible.
The "smaller upper hose" logic in that article is goofy. If you compare the opening in a thermostat vs the size of the upper hose in most vehicles it becomes obvious that the thermostat is the restriction, not the upper hose. A restriction in the outlet would tend to reduce flow somewhat, but there is a greater benefit to that. It is that the coolant pressure created in the engine between the pump and the restriction helps to prevent cavitation and reduces the occurrence of localized hot spots which, in the absence of pressure, could result in steam bubbles forming at those locations.
Just to add a bit more, there are high flow water pumps and high flow thermostats. Certainly are not marketed to keep coolant temps higher.
That’s entirely possible. My Dads friend and one of his sons raced locally at Stockton 99 Speedway, way back when. I was over at the shop when they were buttoning up an engine back from their machine shop. He put a restrictor in, not a thermostat. When got done I asked him why. He said it maintained a better operating temperature at RPMs, and no chance of sticking causing issues. When I asked “why not just leave it open’ ? He told me they wanted to keep the temperature as high as possible to make more power. He then took me to a a cabinet that had at least 10 of the plates with different sized holes he’d use based of what the outside temperature would be. I was maybe 13-15 years old, kinda ran out of questions after that
Cavitation is more a problems with pre 37 fords which had a suck through water pump. the high vacuum created caused by the water pump sucking hot water through the motor caused it to cavitate at relatively low flow rates and at low water temperatures. All modern water pumps are blow through type so its not such an issue. restricting the flow out of the top hose definitely helps with pump cavitation on pre 37 fords where the water pump is in the head.
Excessive velocity can result in cavitation in any pump system due to the production of bubbles on the metal surface. The fluid doesn't know the year or design of the engine. Cavitation is more commonly found in low pressure areas (pump impeller inlets, etc.) and can occur in any fluid system.
Nope... suck through water pumps cause low pressure in the water jacket lowering the boiling point of water. This in turn causes cavitation in the pump as the water flashes off into steam. Its also not helped by early systems being open to atmospheric pressure.
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