440 over heating problem

[PlumCraZRT]

Ok a little confused about something mentioned earlier... maybe someone can clarify? How can a higher velocity water pump reduce heat transfer? I would think that the heat transfer would increase. Simply because whatever mass flow rate you have coming out, would create an equal mass flow coming in, always. I understand the logic, it doesn't have time to cool off, but that shouldn't matter, the same amount is coming into the system. I would think that velocity should always increase heat transfer? Maybe the higher velocity creates unwanted pressure changes? ...I guess That could cause a reduction in heat transfer. Or is my linear relationship assumption between velocity and heat transfer just wrong? Is there a saturation poin if you will? A speed that's just too much or impracticle?

The faster the fluid flows, the more uniform the fluid temp will be throughout the block.  Having "too much flow" would never be a problem.

[72cudamaan]

The faster the fluid flows, the more uniform the fluid temp will be throughout the block.  Having "too much flow" would never be a problem.

But if the coolant doesn't stay in the radiator long enough for the air flow to wick
the heat away from the fins then it won't cool down. Someone else mentioned that a 30/70
mixture is best. I usually don't disagree but it has been proven that 50/50 mixture dissipates heat faster
then any other mixture of glycol and water. Glycol used straight hinders cooling but when you mix the
comcentrate with water, it's effectiveness increases.

[74CudaDave]

I've read several posts all over about using lower or no antifreeze in the cooling system, so I tried that (25/75 antifreeze/coolant, with a bottle of water wetter) this year and without changing anything else, I'm running much cooler than I was with a 50/50 mix. Not a winter driven car and garage stored.

[PlumCraZRT]

But if the coolant doesn't stay in the radiator long enough for the air flow to wick
the heat away from the fins then it won't cool down.

I agree that you will cool the fluid in the radiator more if it's in there longer, but what's missing is that the fluid coming into the radiator will be much hotter if the fluid moves slower.

From a thermodynamic standpoint, it's a closed system, so the heat you create is the heat you dissipate.  If you move the coolant slower, you get hotter fluid into the radiator and cooler fluid out.  If you move the coolant faster, you get cooler fluid into the radiator and hotter fluid out (which I would rather have).

[Strawdawg]

I agree that you will cool the fluid in the radiator more if it's in there longer, but what's missing is that the fluid coming into the radiator will be much hotter if the fluid moves slower.

From a thermodynamic standpoint, it's a closed system, so the heat you create is the heat you dissipate.  If you move the coolant slower, you get hotter fluid into the radiator and cooler fluid out.  If you move the coolant faster, you get cooler fluid into the radiator and hotter fluid out (which I would rather have).

X2

Science does not lie

The faster the fluid moves in a "closed Loop" system, the faster it gets back around for another pass.  As he said prior, a higher velocity in the coolant reduces hot spots inside the block and reduces the likelihood of localized detonation.  Higher velocity of coolant flow thru the radiator tubes also increases turbulence in the tubes which increases the heat transfer to the tubes/fins.

The thermostat is not there to slow the coolant down.  Obviously it is there to set a minimum operating temp and to get the engine up to that temp as soon as possible to in order to reduce engine wear.  It also serves to increase the pressure inside the engine to raise the boiling point of the coolant beyond that created by the radiator cap.   Sometimes, if one adds a high flow thermostat with a standard water pump, then it is possible to see a drop in pressure inside the block which lowers the boiling point and hot spots may develop.  For this reason, a high flow water pump should be installed along with the less restrictive thermostat.  The increased flow will build the pressure back up.

There can be a problem with older vertical tube radiators because the high pressure coming thru the thermostat is on the same side of the radiator as the radiator cap and sometimes it can overpower the spring in the cap.   This is not a problem with horizontal tubed radiators because the cap is on the opposite side of the tubes from where the water enters.

[AARuFAST]

U said u replaced the flex fan with a thermostat controlled fan??? Do u mean a Clutch Fan. Is the Clutch fan new?
If not new With engine off  spin the clutch fan. If it spins more than 1 1/4 turns  replace it .

Your clutch fan should have a thermostat on the front of it for a/c cars, with shroud.
Get rid of the aluminum water pump. Should be cast iron....Got one at pepboys.
A/C water pumps should have 4 blades with thermostat on front, non A/C  6 blades....

I know others with all different makes of cars have trouble with the aluminum radiators...
Are u sure ur gauge is accurate.
Remove belts to a/c
Post a picture of rad, a/c,

[Topcat]

But if the coolant doesn't stay in the radiator long enough for the air flow to wick
the heat away from the fins then it won't cool down. Someone else mentioned that a 30/70
mixture is best. I usually don't disagree but it has been proven that 50/50 mixture dissipates heat faster
then any other mixture of glycol and water. Glycol used straight hinders cooling but when you mix the
comcentrate with water, it's effectiveness increases.

I disagee.

My daily driver runs 100 percent anti freeze and never over heats. Also rust never dis-colors the fluid.

[brads70]

I disagee.

My daily driver runs 100 percent anti freeze and never over heats. Also rust never dis-colors the fluid.

Are you sure it's 100% antifreeze and not just premixed? I've never heard of someone using a 100%  mixture before?

[Chryco Psycho]

100% will work in a warm climate but in cold climate it will gell 75% is about max & is good to - 50* or so , however Ihave worked in -66C , not sure what happens at that point , probably why the engines never get shut off

[Strawdawg]

Must be a mix....the companies have figured out they can make a lot more money selling a half gallon of coolant diluted with a half gallon of water.

the maximum cooling protection is right at 70%.  Once that level is reached, the protection point begins to rise.  100% coolant will freeze at 10F/-12C

Pure coolant has about 50% the heat capacity of pure water.  Therefore, a 50-50 solution will remove approximately 75% of the heat that pure water will.  This means a larger cooling system is required to operate as efficiently as one on pure water.

[Topcat]

100% will work in a warm climate but in cold climate it will gell 75% is about max & is good to - 50* or so , however Ihave worked in -66C , not sure what happens at that point , probably why the engines never get shut off

Yes out here it never gets under 32F.

[high perf mopar]

i used to have a heating problem using "aftermarket aluminum water pump housings",,non mopar,,as per the op states..installed the MP unit from summit and the problem went away,using factory style 3 core copper radiator,with milodon paddle wheel high flow pump.

turns out the water passages of the after market non mopar units restricted the coolant flow..the factory piece i could get 2 fingers in the passage way,,the other,i could not get my little finger in the passage way..

[oldkimmer]

..................Put in a 195 T stat........it will slow down the coolant long enough to cool the engine....also drill a 1/8th in hole in the flange to help remove air from the system.....kim.......

[mopar12372]

 

..................Put in a 195 T stat........it will slow down the coolant long enough to cool the engine....also drill a 1/8th in hole in the flange to help remove air from the system.....kim.......

[footin70rt]

If your running the 440 source water pump housing that may be the problem due to the restriction of the passages. Also here is a very good explanation of the cooling system operation.

http://www.stealth316.com/misc/grapeape-coolingsystems.pdf