Does This Debunk the "Coolant Can Flow Through the Radiator Too Fast" Idea???

[harrisonm]

There is a thread on FABO now about a thermostat gasket leaking. One contributor mentioned that he installed a Flowcooler high flow water pump and his leak started then. I had never heard of Flowcooler High Flow water pumps, so I went to their website. I read the "Common Questions about High Flow pumps" section on their website. It was very interesting. It is a short read.

Considering how many comments/threads/problems we hear about engines running hot, I think this is a very good thing to read. My engine runs a little hotter than I would like. I think I might try one of their pumps. I am not easily convinced by high pressure, phony sales claims. The data in this short article make a lot of sense to me. One thing I found interest was this:

" Hold on...doesn't the coolant have to have more time in the radiator to cool? No. But a lot of people still think so. We have come up with some explanations for the Doubting Thomas."

What they said was very interesting. Please take a look at it.

Commons Questions about Hi Flow Pumps

 

[mopowers]

Unfortunately, this is a myth that will just never die.

 

[66fyssh]

I put one in the 5.9 Magnum when I added a cam snout extension. Seems to cool better, but I haven't been in a lot of stop and go to really test it.

 

[HemiSSDart]

And they also probably think an aluminum radiator cools better than a copper/brass one...

 

[Syleng1]

And they also probably think an aluminum radiator cools better than a copper/brass one...

Aaaah! The Alumium is way cheaper than copper trick. So it must cool better than copper. lol! Nothing cools better than copper radiators.

The radiator shop I use mostly builds heat exchangers and cooling systems for large building chillers and a/c systems all over the world. Why they still do radiators for cars and trucks I have no ideas. Anyhow, they build them out of copper. They must work.

 

[RustyRatRod]

There is a thread on FABO now about a thermostat gasket leaking. One contributor mentioned that he installed a Flowcooler high flow water pump and his leak started then. I had never heard of Flowcooler High Flow water pumps, so I went to their website. I read the "Common Questions about High Flow pumps" section on their website. It was very interesting. It is a short read.

Considering how many comments/threads/problems we hear about engines running hot, I think this is a very good thing to read. My engine runs a little hotter than I would like. I think I might try one of their pumps. I am not easily convinced by high pressure, phony sales claims. The data in this short article make a lot of sense to me. One thing I found interest was this:

" Hold on...doesn't the coolant have to have more time in the radiator to cool? No. But a lot of people still think so. We have come up with some explanations for the Doubting Thomas."

What they said was very interesting. Please take a look at it.

Commons Questions about Hi Flow Pumps

I've preached it and preached it to deaf ears. you need to get the coolant out of the engine and into the radiator as quickly as possible. People simply will not believe it.

 

[abodyjoe]

i would totally expect a high flow water pump seller so say that...


i have one of their pumps on the 360 thats in the dart..

 

[72bluNblu]

Same as always. Guys that barely graduated high school arguing thermodynamics.

No, you can’t flow water through the radiator too fast to cool it. An old wives tale for sure, but we’ve beaten that horse to death many times and people will never let go of it.

You can spin a pump too fast, which can cause cavitation and that will hurt the cooling of the whole system. So you have to match the pulley size/engine RPM to what the pump is designed to work at. But too fast through the radiator to transfer heat? No.

And the brass vs copper thing again, oh boy!

Yes, copper has better thermal conductivity than aluminum does. Absolutely true. But you can run larger and thinner tubes in aluminum compared to copper because of the differences in material properties. So can an aluminum radiator cool better than a copper radiator? Yes, it can.

But it depends on the application. If you build two identical radiators based on the copper/brass radiators construction, the copper/brass radiator will cool better. But if you use larger tubes in the aluminum radiator than you can use in the copper/brass radiator, it’s not as clear. You’re not typically comparing apples to apples, a radiator design made to maximize the properties of aluminum is different than the design that would be used for copper/brass. So you have to compare the individual radiators, it’s not as easy as saying copper is better than aluminum.

Here’s some basics of it, of course the info is from Griffen so…

https://www.motortrend.com/how-to/ccrp-0211-aluminum-or-copper-radiator-for-your-car/

 

[Kern Dog]

Aaaah! The Alumium is way cheaper than copper trick. So it must cool better than copper. lol! Nothing cools better than copper radiators.

The radiator shop I use mostly builds heat exchangers and cooling systems for large building chillers and a/c systems all over the world. Why they still do radiators for cars and trucks I have no ideas. Anyhow, they build them out of copper. They must work.

People like to refer to OEM type radiators as copper. I'm guilty of that too. They are far more brass than copper...

 

[RustyRatRod]

Same as always. Guys that barely graduated high school arguing thermodynamics.

No, you can’t flow water through the radiator too fast to cool it. An old wives tale for sure, but we’ve beaten that horse to death many times and people will never let go of it.

You can spin a pump too fast, which can cause cavitation and that will hurt the cooling of the whole system. So you have to match the pulley size/engine RPM to what the pump is designed to work at. But too fast through the radiator to transfer heat? No.

And the brass vs copper thing again, oh boy!

Yes, copper has better thermal conductivity than aluminum does. Absolutely true. But you can run larger and thinner tubes in aluminum compared to copper because of the differences in material properties. So can an aluminum radiator cool better than a copper radiator? Yes, it can.

But it depends on the application. If you build two identical radiators based on the copper/brass radiators construction, the copper/brass radiator will cool better. But if you use larger tubes in the aluminum radiator than you can use in the copper/brass radiator, it’s not as clear. You’re not typically comparing apples to apples, a radiator design made to maximize the properties of aluminum is different than the design that would be used for copper/brass. So you have to compare the individual radiators, it’s not as easy as saying copper is better than aluminum.

Here’s some basics of it, of course the info is from Griffen so…

https://www.motortrend.com/how-to/ccrp-0211-aluminum-or-copper-radiator-for-your-car/

C'mon man! lol Plenty of smart people never graduated.

That said, my understanding of brass copper is as for cooling, because of all the solder and chemicals and whatnot, that kinda levels the playing field a little. But I've been radiator shopping for my Ford truck very recently. All of the big companies I've spoken with all agree that brass/copper is more durable and generally lasts longer.

 

[72bluNblu]

C'mon man! lol Plenty of smart people never graduated.

That said, my understanding of brass copper is as for cooling, because of all the solder and chemicals and whatnot, that kinda levels the playing field a little. But I've been radiator shopping for my Ford truck very recently. All of the big companies I've spoken with all agree that brass/copper is more durable and generally lasts longer.

I didn’t say anybody was dumb. But high school physics doesn’t give someone the kind of knowledge you need to have a high level thermodynamic properties argument either. The problem is people thinking they know something they don’t have the tools to properly understand.

Like most things, the brass/copper argument is more complicated than just “copper has a higher conductivity number than aluminum”. Most automotive brass/copper radiators are more brass. And then they’re soldered together, not welded. And the solder has different properties. And the brass/copper has to be thicker wall, so, now it’s heavier. Well, more mass means more stored energy which has to be dissipated. So if the brass/copper radiator weighs more (and they do) then it loses efficiency compared to a lighter one.

Like I said, it depends. It’s not as clear cut as saying “copper cools better” or “aluminum cools better”. There are aluminum radiators that will outperform brass/copper radiators. There are brass/copper radiators that will outperform aluminum ones. And they will not have the same number of tubes/fins, so their cooling surface areas will be different even for a radiator with the same external dimensions.

You can’t just compare brass/copper vs aluminum as materials, you have to compare the radiators as they’re constructed. And the weight, surface area, fin density, tube diameter etc all make a difference. So you can have a radiator that doesn’t have the highest thermal conductivity cool better than one that does, based entirely on the specific construction.

 

[harrisonm]

I've preached it and preached it to deaf ears. you need to get the coolant out of the engine and into the radiator as quickly as possible. People simply will not believe it.

Same as always. Guys that barely graduated high school arguing thermodynamics.

No, you can’t flow water through the radiator too fast to cool it. An old wives tale for sure, but we’ve beaten that horse to death many times and people will never let go of it.

You can spin a pump too fast, which can cause cavitation and that will hurt the cooling of the whole system. So you have to match the pulley size/engine RPM to what the pump is designed to work at. But too fast through the radiator to transfer heat? No.

And the brass vs copper thing again, oh boy!

Yes, copper has better thermal conductivity than aluminum does. Absolutely true. But you can run larger and thinner tubes in aluminum compared to copper because of the differences in material properties. So can an aluminum radiator cool better than a copper radiator? Yes, it can.

But it depends on the application. If you build two identical radiators based on the copper/brass radiators construction, the copper/brass radiator will cool better. But if you use larger tubes in the aluminum radiator than you can use in the copper/brass radiator, it’s not as clear. You’re not typically comparing apples to apples, a radiator design made to maximize the properties of aluminum is different than the design that would be used for copper/brass. So you have to compare the individual radiators, it’s not as easy as saying copper is better than aluminum.

Here’s some basics of it, of course the info is from Griffen so…

https://www.motortrend.com/how-to/ccrp-0211-aluminum-or-copper-radiator-for-your-car/

I know this topic has been beaten to death here. I just really liked the way the referenced article explained it. I personally never believed the story about water needing to flow through the radiator slower. You are also leaving it in the hot engine block longer.

 

[RustyRatRod]

I know this topic has been beaten to death here. I just really liked the way the referenced article explained it. I personally never believed the story about water needing to flow through the radiator slower. You are also leaving it in the hot engine block longer.

Yeah it's a good article. Thanks for postin it. It kinda breaks it down so it really can't be argued with. Yet some people still will.

 

[harrisonm]

Yeah it's a good article. Thanks for postin it. It kinda breaks it down so it really can't be argued with. Yet some people still will.

Aint that the truth.

 

[azaustin]

I ran Flowkooler water pumps on my ‘90 Bronco with a 351 and my 2000 F250 7.3. In both installations the engine ran cooler. Not only that, the pumps on both trucks outlasted the stockers and actually never failed. I swapped out the stock pump on the Bronco at around 90k. I put it on the new rebuilt motor at 170k+ and it was stil on the motor when I sold the truck at nearly 300k. The stock 7.3 pump packed it in at 80k. The FK was on it when I traded it in on a Jeep at 211k. Good stuff.

 

[circlepilot]

I ran a large brass radiator out of a late 50's pickup truck in my 75 Nova dirt track car for 3 seasons (until it got destroyed) and I never had any overheating problems. I would see cars with aluminum radiators dropping out of races or destroying engines from overheating. It held "a lot" of water.

 

[Newbomb Turk]

And they also probably think an aluminum radiator cools better than a copper/brass one...

It does. That’s a PROVEN FACT.

 

[Newbomb Turk]

I ran a large brass radiator out of a late 50's pickup truck in my 75 Nova dirt track car for 3 seasons (until it got destroyed) and I never had any overheating problems. I would see cars with aluminum radiators dropping out of races or destroying engines from overheating. It held "a lot" of water.

How is that the radiators fault?

The OEM’s have all gone to aluminum. Are they wrong too?

You run the biggest radiator you can fit.

You use the best high flow water pump you can find.

You use a Stewart Components high flow thermostat.

You speed up the water pump until you the belts fly off or you see cavitation. And IMO if it you do see cavitation I’d be looking at the pump first and not the speed of it.

No clutch fans.

Then pick a thermostat opening you want. That will set your minimum operating temperature. If it won’t stay within 10 degrees of it’s temperature you need to keep working on it.

And BTW, most of the CT guys I know still think UNDERdriving the water pump to save 4 horsepower while giving up 20 plus horsepower because they can’t keep the engine cool.

And telling them that won’t work. So I just change the pulleys and tell them drive it or take my engine out.


The funny thing is a retarded third grader can walk up and look at the pulleys and see if it’s under or overdriven.

 

[72bluNblu]

It does. That’s a PROVEN FACT.

This is a massive oversimplification, just like saying the opposite is.

It’s not, at least certainly not in all cases. The material for brass/copper does have a better thermal conductivity coefficient. It depends entirely on the particular construction of the radiator in question. For some applications aluminum will perform better, for others brass/copper will. It will literally some down to the construction of the individual radiators you’re comparing.

How is that the radiators fault?

The OEM’s have all gone to aluminum. Are they wrong too?

You run the biggest radiator you can fit.

You use the best high flow water pump you can find.

You use a Stewart Components high flow thermostat.

You speed up the water pump until you the belts fly off or you see cavitation. And IMO if it you do see cavitation I’d be looking at the pump first and not the speed of it.

No clutch fans.

Then pick a thermostat opening you want. That will set your minimum operating temperature. If it won’t stay within 10 degrees of it’s temperature you need to keep working on it.

And BTW, most of the CT guys I know still think UNDERdriving the water pump to save 4 horsepower while giving up 20 plus horsepower because they can’t keep the engine cool.

And telling them that won’t work. So I just change the pulleys and tell them drive it or take my engine out.


The funny thing is a retarded third grader can walk up and look at the pulleys and see if it’s under or overdriven.

You’re making a ton of assumptions here. Just because the OEM’s have all gone aluminum/plastic doesn’t mean that’s the best for a particular application.

Aluminum is cheaper, which is a factor. Aluminum/plastic is a lot cheaper. It’s also lighter, so for overall mass reduction you can be looking at better fuel efficiency which is a benchmark that the OEM’s have to hit. Aluminum radiators can typically also withstand higher pressures because of their construction, which is also very helpful because it raises the boiling temperature on newer cars that work better when run hotter because of other requirements.

As for the rest of it, the best cooling system is one that has components that are matched to work together. Just slapping on a higher output pump isn’t always the answer. Running the pump at the speed it was designed is best, so underdriving or overdriving it can both result in issues. And whether or not a particular engine’s water pump is under or overdriven doesn’t tell you much, sure, you can look at the pulley size and see if it is. But just on our cars Ma Mopar ran both under and overdriven pulleys on literally the same model of engine depending on whether or not the car had AC. And further, used two different pumps, one that was under driven and one that was overdriven. So unless you already know that was stock seeing a pump that’s over or under driven doesn’t tell you anything.

If you’re running a mechanical fan, having some kind of clutch fan is a GOOD thing. Working properly it should only reduce the speed of the fan when the car is moving, and they airflow from the speed of the car is doing the work so the fan doesn’t need to be. A direct drive mechanical fan is just wasting power when the car is doing anything much better than 25 mph. Which is one reason that electric fans are a great improvement in efficiency, because you only run them when you need to. If you need the fan running 100% when doing highway speeds, you have another issue.

 

[Newbomb Turk]

This is a massive oversimplification, just like saying the opposite is.

It’s not, at least certainly not in all cases. The material for brass/copper does have a better thermal conductivity coefficient. It depends entirely on the particular construction of the radiator in question. For some applications aluminum will perform better, for others brass/copper will. It will literally some down to the construction of the individual radiators you’re comparing.



You’re making a ton of assumptions here. Just because the OEM’s have all gone aluminum/plastic doesn’t mean that’s the best for a particular application.

Aluminum is cheaper, which is a factor. Aluminum/plastic is a lot cheaper. It’s also lighter, so for overall mass reduction you can be looking at better fuel efficiency which is a benchmark that the OEM’s have to hit. Aluminum radiators can typically also withstand higher pressures because of their construction, which is also very helpful because it raises the boiling temperature on newer cars that work better when run hotter because of other requirements.

As for the rest of it, the best cooling system is one that has components that are matched to work together. Just slapping on a higher output pump isn’t always the answer. Running the pump at the speed it was designed is best, so underdriving or overdriving it can both result in issues. And whether or not a particular engine’s water pump is under or overdriven doesn’t tell you much, sure, you can look at the pulley size and see if it is. But just on our cars Ma Mopar ran both under and overdriven pulleys on literally the same model of engine depending on whether or not the car had AC. And further, used two different pumps, one that was under driven and one that was overdriven. So unless you already know that was stock seeing a pump that’s over or under driven doesn’t tell you anything.

If you’re running a mechanical fan, having some kind of clutch fan is a GOOD thing. Working properly it should only reduce the speed of the fan when the car is moving, and they airflow from the speed of the car is doing the work so the fan doesn’t need to be. A direct drive mechanical fan is just wasting power when the car is doing anything much better than 25 mph. Which is one reason that electric fans are a great improvement in efficiency, because you only run them when you need to. If you need the fan running 100% when doing highway speeds, you have another issue.

I agree. But we aren’t talking earth moving equipment or junk like that.

If you radiator won’t cool and it’s aluminum, it’s not not cooling because of what it’s made from.

So my over simplifications aren’t really.

They are facts.

Almost no one disputes that two big cores will out cool four smaller cores. You aren’t building a radiator out of brass or copper or some mix of it that will tolerate two big cores.

Again, that’s a fact not a simplification.

If guys would figure out that skimping on cooling causes power losses because you can’t set and control engine temperature then they’d follow the simple rules outlined above.

I didnt make those up. Those came from the industry.

A few simple phone calls to a couple of places and anyone can learn what I posted.

Buying undersized junk **** and not grasping what it means when you have a 180 degree thermostat and the engine on hot days is running at 200 they should know their cooling system is NOT doing its job.

It’s failing at its job.

Guys will argue if it ain’t piking water out it ain’t hot and I call bullshit on that thinking.

Again, if you are 180 on the thermostat and 200 on the gauge it’s TOO HOT.

If that’s not too hot, get a 195 thermostat. Of course that’s not the fix for a piss poor designed cooling system.

I just don’t get why people don’t understand why the above scenario is wrong.

 

[cosgig]

I agree. But we aren’t talking earth moving equipment or junk like that.

If you radiator won’t cool and it’s aluminum, it’s not not cooling because of what it’s made from.

So my over simplifications aren’t really.

They are facts.

Almost no one disputes that two big cores will out cool four smaller cores. You aren’t building a radiator out of brass or copper or some mix of it that will tolerate two big cores.

Again, that’s a fact not a simplification.

If guys would figure out that skimping on cooling causes power losses because you can’t set and control engine temperature then they’d follow the simple rules outlined above.

I didnt make those up. Those came from the industry.

A few simple phone calls to a couple of places and anyone can learn what I posted.

Buying undersized junk **** and not grasping what it means when you have a 180 degree thermostat and the engine on hot days is running at 200 they should know their cooling system is NOT doing its job.

It’s failing at its job.

Guys will argue if it ain’t piking water out it ain’t hot and I call bullshit on that thinking.

Again, if you are 180 on the thermostat and 200 on the gauge it’s TOO HOT.

If that’s not too hot, get a 195 thermostat. Of course that’s not the fix for a piss poor designed cooling system.

I just don’t get why people don’t understand why the above scenario is wrong.

So, are you saying that a 160 thermostat should keep the engine running at 160 degrees?

 

[Newbomb Turk]

So, are you saying that a 160 thermostat should keep the engine running at 160 degrees?

Yes. If it won’t do that the cooling system is not keeping up.

I’d love to be able to not run a thermostat at all. I don’t want or need that restriction.

And I tried that. It was a hundred degrees out and about 90 in the shop. I barely got 140 degrees out of it. That’s too cold to run the defrost in the winter.

So I use a 160 thermostat to set my minimum temperature. If my cooling system wasn’t capable the engine would run hotter than what the thermostat is rated to open.

As it is, on 100 degree and hotter days if I have to sit at a long light it will creep up to 170.

That’s because I’m only turning the water pump 6% over crank speed.

I’d bet everything I have, everything you have and a bunch of stuff neither of us have that if I can drive the water pump 20% faster than the crank that I could sit at a stop light in downtown hell all day and it would stay at 160.

 

[ir3333]

Run Forest Run. If you are relying on the speed of your water pump to cool your engine you don't understand how your cooling system works. The rad is the heat exchanger and it must be the correct size and design to remove the the heat your engine produces.

 

[Newbomb Turk]

Run Forest Run. If you are relying on the speed of your water pump to cool your engine you don't understand how your cooling system works. The rad is the heat exchanger and it must be the correct size and design to remove the the heat your engine produces.

Did you read what I wrote? It ain’t just about pump speed. That is PART of how you do it.

Pump speed matters. Chrysler knew it and published the information.

We don’t need to guess.

 

[72bluNblu]

If you radiator won’t cool and it’s aluminum, it’s not not cooling because of what it’s made from.

I agree, in our application if a car isn’t cooling it’s not because the radiator is aluminum

So my over simplifications aren’t really.

They are facts.

Almost no one disputes that two big cores will out cool four smaller cores. You aren’t building a radiator out of brass or copper or some mix of it that will tolerate two big cores.

Again, that’s a fact not a simplification.

Actually it is again a wild oversimplification. Because if we’re talking about a 4 core brass/copper radiator and a large tube 2 core aluminum radiator it is NOT a slam dunk that the aluminum radiator will cool better. It simply is NOT a fact. You’d have to test those individual radiators, and the result would depend on the individual construction. It could easily go either way.

Saying otherwise is simply a wild *** guess.

Buying undersized junk **** and not grasping what it means when you have a 180 degree thermostat and the engine on hot days is running at 200 they should know their cooling system is NOT doing its job.

It’s failing at its job.

Nope. Another simplistic over generalization.

Yes, the thermostat only sets the minimum temperature.

In general your cooling system should be able to maintain a temperature within the operating range of the engine. The thermostat has no effect on that, it’s out of the loop the moment it fully opens. So if your car maintains 180, or 190, or 200 once the thermostat is open that has nothing to do with the thermostat and everything to do with your engine, it’s tune, and your cooling systems capabilities. If you run a 160° thermostat and your car will maintain 190° regardless of the situation it doesn’t indicate an issue with the cooling system at all.

Yes. If it won’t do that the cooling system is not keeping up.

I’d love to be able to not run a thermostat at all. I don’t want or need that restriction.

And I tried that. It was a hundred degrees out and about 90 in the shop. I barely got 140 degrees out of it. That’s too cold to run the defrost in the winter.

So I use a 160 thermostat to set my minimum temperature. If my cooling system wasn’t capable the engine would run hotter than what the thermostat is rated to open.

As it is, on 100 degree and hotter days if I have to sit at a long light it will creep up to 170.

That’s because I’m only turning the water pump 6% over crank speed.

I’d bet everything I have, everything you have and a bunch of stuff neither of us have that if I can drive the water pump 20% faster than the crank that I could sit at a stop light in downtown hell all day and it would stay at 160.

This is silly. Why are you worried about the “restriction” from the thermostat if your cooling system works well?

As for the amount of over or under drive it totally depends on the pump itself and the rest of the system. AC Mopars were overdriven at 30-40%.

As far and maintaining within 10°, sure, that indicates a robust cooling system, but that’s not a standard that indicates anything less is junk. If your car maintains 180° all day with a 160° thermostat you’ve got no issues at all.

Run Forest Run. If you are relying on the speed of your water pump to cool your engine you don't understand how your cooling system works. The rad is the heat exchanger and it must be the correct size and design to remove the the heat your engine produces.

Nope, not true. Pump speed is very important, and has to be matched. Again, Ma Mopar changed the speed of the pump by over 30% depending on the engine and options. It’s not the only thing, but it’s a thing. There are several threads here where members solved their overheating issues just by changing their pump drive ratio. Mostly after realizing they were unintentionally under driving their water pump.