Running without a thermostat ok?

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yeah, I get it, I'm :banghead:.

Not my fault people don't understand how their radiators work. Although I should probably know better by now than to get worked up about it. Not my car, not my problem.

This is fast becoming my attitude. My truck runs with the temp gauge needle between the first mark next to the "C" and the first mark to the right of it. Just at the beginning of the range. Everything is there the factory installed. No short cuts, no stupidness, although I did install a Mr Gasket high flow 180* thermostat when I flushed the cooling system. It wasn't overheating, I simply wanted a baseline when I bought the truck, so I serviced everything.

"MY" vehicle runs fine. I don't give a crap about much else.
 
They call it a cooling system for a reason. Once you start removing parts of that system, the problems start showing up. We have been through this hundreds of times on here.

My car, running a complete factory cooling system, with an AC condenser in front of the radiator, could idle all day, on a 100 degree day, without overheating.

Get the correct thermostat, use a fan shroud, use a real fan that can move some air, have an adequately sized radiator in good condition, use a good and correct cap, and run coolant.
 
Couldn't have said it better ^^^^^^^^
 
Can we assume a new radiator cap went on the new radiator ? Does oil pressure drop very low when the engine gets hot ? Oil flow does effect engine temp
Yes, new cap also. And fresh 50/50 coolant after a good flushing but that was a few months ago when I replaced the radiator. Oil pressure remains consistent as from before the original temp increases. Starts out at around 40 and drops about 5 psi when warmed up to operating temp with variations depending on rpm.

Today was overcast, actually rained a few minutes, and outdoor temps dropped down to the high 80s this afternoon. She ran at around 185-190* and never rose about 195*. I feel everything is functioning correctly.

Sorry to start all this debate :finga: My only real concern is what temp would be considered "too hot" and I should pull over and let her cool down before I damage anything. My OEM gauge starts at 120* and peaks at 250*. Most of my other older vehicles I have owned only went up to 220*. Thanks to all for the education, input and advice!
 
"MY" vehicle runs fine. I don't give a crap about much else.


I think this will be my new end all be all policy next time anyone chooses to tell me how stu-stu-stupid I am.

Glad your "truck" runs fine.

My **** works, my **** wins.

I also must say how some seem to be able to say the same things as others or disagree and yet not receive the wrath.
 
68 formula you're exactly right. I haven't touched the cooling system on my Dart for years. It has a/c also and will idle out in the sun forever with no issues. I am sort of waiting for it to fail, freeze plug or something, to give me an excuse to pull the engine since it uses a little oil and has a problem valve. Also this thread prompted me to go out and give my old Cobalt with a couple hundred thousand on it a test. It got a new radiator and condensor when it was fairly new due to a rather large raccoon. Other than that untouched. It usually runs about 193, but by taking it up hill air on and floorboarded I could only manage 219. It is about 111 degrees here. These threads about overheating vehicles are difficult, there are just too many variables that many don't get. What is so hard about looking up your car and putting the thermostat in it that it is supposed to have? Seems that would be a good place to start.
 
My F250 6.9 International has a triple core radiator and I'm worried because it never gets hot.
Good thing I rarely have to drive it.
 
It usually runs about 193, but by taking it up hill air on and floorboarded I could only manage 219.
So apparently, 219* is not a cause for concern? If my old truck got up to 220*, I'd be sitting on the side of road in the shade and waiting for it to cool down. Btw, yes, spec'd, purchased, pre-tested, and installed new thermostat.
 
The only idiot light info I actually remember was small block chevy. Light came on at 237 if all was functioning properly. My truck will go to close to 250 before it goes into shut down mode.
 
Through a series of strange happenings with egr, egr cooler, my turbo instantly pumped my cooling system beyond its capabilities and exploded my upper hose. At 80ph it didn't take long for all the bells and whistles to go off. A little duct tape and a few gallons of water and I was home. The repair will go into the hundreds. Just love a failed system or two.
 
Water takes time to absorb heat, it takes time to shed heat. But unless your engine is made of transparent aluminum, I doubt the coolant is teleporting itself from the water pump to the thermostat housing, which means its spending time in the engine. The flow speed generated by engines isn't enough to keep the water from absorbing significant heat energy. There's simply too much restriction to let it flow THAT fast.

Water does transmit heat about 130x slower than iron though (at room temperature and pressure), which means that if the block is at or near the boiling point of the coolant, we need a way to mitigate aeration caused by the boiling because water near the hottest spot will boil first (much like the bottom of an egg burning first).

Our water pumps are basically belt-drive superchargers moving water. They will build 'boost' just like any other impeller system, and the more restriction down-stream the more they'll build for a given energy input (other trade offs not withstanding, such as cavitation and turbulence).

So what we have is a fine balance of restriction vs flow that helps to create the pressure we want to keep the coolant in contact with the inside of the engine surfaces to keep it doing it's job. As the mass of coolant increases it's temperature (since air-cooling isn't efficient enough to get the coolant back to ambient air temp during it's ride through the radiator) the pressure built by the pump alone isn't enough, typically, so we have pressurized caps to add even more of a 'buffer'. Increasing the power of an engine will increase the amount of waste heat which manifests as hotter internal block temperatures which means we need even greater pressure (high flow water pumps) to counteract the localized boiling.

Lower temperature thermostats will only reduce the running temperature of an engine if the radiator is up to the task of shedding the heat sent to it. If it's not, then lowering the thermostat temperature can have the opposite effect: the restriction it offers will be reduced at higher temperatures since it's open more and sooner and the total pressure in the block is reduced to the point where it is POSSIBLE in SOME CASES to allow boiling to occur. When it does, a runaway situation typically happens and we get an overheating system. Typically, if a system is this marginal, it won't fall into the narrow range where a hotter thermostat actually helps with hot running, but it CAN happen.

So: running without a thermostat does exactly as the self-appointed (and some actual) engineers point out: it increases warm up times (your rings and oil will love this), eliminates the restriction needed to build pressure in the block to help mitigate local boiling (which aerates the coolant and effectively reduces the surface area of the coolant in contact with the block) and will generally screw things up. Some systems will run hotter without, some will simply run stone cold. As with most things, the reality depends on the variables.

A 195T stat'd engine can run at 180 degrees. The 195 is probably beginning to open up at 180, and there are certainly other passage ways for coolant to take through the system (heater core, anyone?) and at the small opening it's seeing at 180 it's likely helping to build some significant pressure to help quell any localized boiling.

There are very small effects that flow speed can have, mostly with boundary layer thickness and shear of the fluid, but we're likely not going to see conditions where those are the driving characteristics of the system. Temperature and pressure are going to dominate and occasionally there will be someone with issues which can be attributed to flow speed, but they're going to tend to be the exception and not the rule.

As far as Chernobyl, it had nothing to do with cooling towers. The cooling system and it's poor design (but typical of the time) didn't help, but it wasn't the cause. Wikipedia has a pretty good run down on what exactly happened.
 
"As far as Chernobyl, it had nothing to do with cooling towers. The cooling system and it's poor design (but typical of the time) didn't help, but it wasn't the cause. Wikipedia has a pretty good run down on what exactly happened. "

The aliens did it trying to pay back the Energizer bunny!
 
"As far as Chernobyl, it had nothing to do with cooling towers. The cooling system and it's poor design (but typical of the time) didn't help, but it wasn't the cause. Wikipedia has a pretty good run down on what exactly happened. "

The aliens did it trying to pay back the Energizer bunny!

Shhhhhh! The public isn't supposed to know!

Great... now I have to look out for black helicopters.


...again...
 
please use a T-stat...... nothing hate worse that a car w/o one..... hate that someone started doing that....boooooooo
 
I'm not jumping on one side or the other of this debate but just throwing out my personal experience. Old setup was a standard water pump and 5 blade fan. Car ran around 180-190 most of the time. Now with an electric water pump and no thermostat, it runs around 190 with the electric fan on. I tried a restrictor plate and it actually made the car run hotter. I couldn't get it off 210 degrees cruising on the higway, even with the fan running. Took the restrictor out and it runs cooler again.

Now, to give you an idea of how fast this pump flows. I was flushing the whole coolant system the other day. I was going to run a water hose in the radiator fully open from the faucet then turn on the pump. The idea was to turn the pump on, let the water hose feed water, and the upper radiator hose I had routed to a pvc pipe going out of the system. I filled the radiator and put the hose on the ground so water wasn't spewing everywhere out the top. What I would do is lean into the car, hit the pump switch, and go grab the hose and keep feeding water and get everything good and flushed. Well that was the idea. I hit the switch, ran to the hose, and by the time I grabbed it, the pump was alread done pumping all it could get. This was literally about 2-3 seconds! No exaggeration. Next time I kept the water hose feeding the radiator before I hit the switch. It still only took about 3-4 seconds to pump what it could get. What I was getting out of the hose compared to what the pump was doing was a joke. It is a serious pump! My mind tells me it's flowing WAY too fast, but the restrictor plate made the temps much worse, opposite of what I was expecting. I personally believe it was aeration caused by the restrictor plate, which resulted in less surface are in the coolant across the radiator, but I'm not 100% sure. I'm still looking for a better solution to slow the flow and won't aerate the system. I don't see any reason it shouldn't cool as good as before or better. Just my experience.
 
Did you try testing the thermostat? Maybe it's not functioning properly? A simple thermometer and a pan of water on the stove will tell you when, or if, the thermostat is opening and at what temp!!
 
I was just kind of joking about Chernobyl. However that system was far better than the scoop salt water out of the ocean and dump it on the spent fuel rod method used at Fukushima, the real disaster which is yet to be.
Oh, by the way Phreakish, nice read. Thanks.
 
I'm not jumping on one side or the other of this debate but just throwing out my personal experience. Old setup was a standard water pump and 5 blade fan. Car ran around 180-190 most of the time. Now with an electric water pump and no thermostat, it runs around 190 with the electric fan on. I tried a restrictor plate and it actually made the car run hotter. I couldn't get it off 210 degrees cruising on the higway, even with the fan running. Took the restrictor out and it runs cooler again.

Now, to give you an idea of how fast this pump flows. I was flushing the whole coolant system the other day. I was going to run a water hose in the radiator fully open from the faucet then turn on the pump. The idea was to turn the pump on, let the water hose feed water, and the upper radiator hose I had routed to a pvc pipe going out of the system. I filled the radiator and put the hose on the ground so water wasn't spewing everywhere out the top. What I would do is lean into the car, hit the pump switch, and go grab the hose and keep feeding water and get everything good and flushed. Well that was the idea. I hit the switch, ran to the hose, and by the time I grabbed it, the pump was alread done pumping all it could get. This was literally about 2-3 seconds! No exaggeration. Next time I kept the water hose feeding the radiator before I hit the switch. It still only took about 3-4 seconds to pump what it could get. What I was getting out of the hose compared to what the pump was doing was a joke. It is a serious pump! My mind tells me it's flowing WAY too fast, but the restrictor plate made the temps much worse, opposite of what I was expecting. I personally believe it was aeration caused by the restrictor plate, which resulted in less surface are in the coolant across the radiator, but I'm not 100% sure. I'm still looking for a better solution to slow the flow and won't aerate the system. I don't see any reason it shouldn't cool as good as before or better. Just my experience.


Lots of variables there. It could be as simple as the impellor on the electric pump not being able to build as much pressure despite it's ability to flow very quickly. When you empty the system, there's little restriction. When you run through the block/plate it can offer significant restriction.

That's the hard part with the too-fast-to-cool myth, every observable piece of evidence suggests that it's flow speed. The reality is that pressure is a bigger driver, but pressure isn't as readily observable. That's why I really don't take issue with folks thinking it's flow speed, because there's no way to demonstrate it with the instrumentation normally found on an engine.

I won't get into electric vs mechanical pump drives. Both have their place and only one can keep water circulating with the engine off for racing applications.
 
I personally believe it was aeration caused by the restrictor plate, which resulted in less surface are in the coolant across the radiator

I doubt this is the case. It could DEFINITELY aerate, but by the time the coolant gets through the upper hose it should have subsided enough. If it really was doing this, if you ever popped the cap with it running (warm or not) you'd have had lots of froth in the upper tank of the radiator.

There's lots of things it COULD be, but is shooting in the dark without an impeller map (like a turbo map, basically) to see where the impeller would break down at higher back pressures. Then you'd basically need a coolant 'boost gauge' to see if your impeller was operating in that island or not. Lots of info that probably isn't readily available and would vary significantly depending on the type of coolant, it's temperature, age, etc.

The other way, which is probably how the OEMs did it back in the day, would simply be to see how much pressure builds up in a particular engine configuration based on RPM and then target maximum pressure to coincide with max power production RPM. The electric pump could be 'qualified by similarity' if compared side-by-side with an OEM pump and comparing the pressure behind the tstat. The electric would have to at least match the OEM max at the OEMs 'sweet spot' to be worth it.

A 'step down' in pump performance may not be much issue in a mild race application since you can still pump coolant in between runs with an electric pump - more difficult to do that with a stocker.
 
Lots of variables there. It could be as simple as the impellor on the electric pump not being able to build as much pressure despite it's ability to flow very quickly. When you empty the system, there's little restriction. When you run through the block/plate it can offer significant restriction.

It could also be that the pump simply doesn't flow as much as the stocker does at engine speed. Again, without proper data it's as good as shooting in the dark. If the pump doesn't flow as much, then by the time you build enough pressure to work it may not flow enough to clear the block fast enough to deal with the heat. Hopefully it's the former vs the latter, as the latter would indicate that the electric pump you got was a step down from the OEM unit.

Without measuring the pressure built up in the block by the pump side-by-side with the stocker, as well as comparing flow at various operating RPMs it's near impossible to say what the cause really is.

That's the hard part with the too-fast-to-cool myth, every observable piece of evidence suggests that it's flow speed. The reality is that pressure is a bigger driver, but pressure isn't as readily observable. That's why I really don't take issue with folks thinking it's flow speed, because there's no way to demonstrate it with the instrumentation normally found on an engine.

I won't get into electric vs mechanical pump drives. Both have their place and only one can keep water circulating with the engine off for racing applications.

I agree 100%. Too many variables to compare side by side.
 
I doubt this is the case. It could DEFINITELY aerate, but by the time the coolant gets through the upper hose it should have subsided enough. If it really was doing this, if you ever popped the cap with it running (warm or not) you'd have had lots of froth in the upper tank of the radiator.
Therein lies the issue. With the water neck I'm using, I can't add a standard washer/restrictor plate. I can't even run a thermostat if I wanted to. I won't go into all the details but I simply can't because I'm not using factory type parts. I had the washer at the exit of the upper hose and I could visibly see air in the coolant (not frothy though). That's why I thought it was aeration. Still trying to devise a way to put the washer at the neck exit inside the entrance of the hose without the washer getting pushed sideways. I could add a clamp so that the washer doesn't move, it will just look strange, but be functional. That's probably what I'll try next. Also I'm running pump gas instead of race fuel so that could be adding more heat to the system too.
 
I think this will be my new end all be all policy next time anyone chooses to tell me how stu-stu-stupid I am.

Glad your "truck" runs fine.

My **** works, my **** wins.

I also must say how some seem to be able to say the same things as others or disagree and yet not receive the wrath.

I wasn't sayin you were stupid friend. We all take stupid pills from time to time. I was simply trying to point out that we were really not discussing electric water pumps in this discussion.....at least I was not. Those are not street friendly for the most part. Yeah, I know. You run one or know somebody, blah blah blah. There will always be the exception. I meant no offense.
 
worked for a major truck researce lab this is what we found the shroud is very inporant why the fan only pull air from the area in front of it with out one now the air hit the hot motor and some is forced back to the cornors of the rad. thus a heat problem with the shroud the fan pulls air across the hole rad the was found in wind tunnel test with smoke tracer beleve it or not it dose happen we also test with and with out, big differene
 
worked for a major truck researce lab this is what we found the shroud is very inporant why the fan only pull air from the area in front of it with out one now the air hit the hot motor and some is forced back to the cornors of the rad. thus a heat problem with the shroud the fan pulls air across the hole rad the was found in wind tunnel test with smoke tracer beleve it or not it dose happen we also test with and with out, big differene

Indeed. Fans will pull air from the area of least resistance. The engine compartment is also a very turbulent area. Air exiting the fan meets the engine, and can even meet higher pressure from the underside of the car and revert back toward the low pressure area in front of the fan. The radiator is a pretty big air restriction, it's like a wiffle ball.

When we add a shroud, the fan has fewer 'choices' of places to draw air from and will pull air through the radiator.
At higher speeds, the fan may not be able to evacuate all the air ramming into the radiator, so many shrouds have built in doors which blow-open at speed.

Another trick to help draw air through the radiator is to keep the area under the car and the engine compartment at lower pressure. An air dam can do this, which is why folks add them to help with cooling. Lowering the pressure makes the air want to get through the radiator to the low pressure area to fill it. Keeping a little 'rake' to the car can help too, but not always and rarely consistently.

An air dam and a shroud will usually help immensely. the shroud for low speed and the air dam for higher speeds (if your temp tends to creep up when cruising at highway speeds).
 
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