Re: [Chrysler300] 300G Cooling System Over Heating..
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Re: [Chrysler300] 300G Cooling System Over Heating..

Thanks for the physics lesson. Reminds me of my college days. My post was a simplified description in layman's terms, so those who are without a PhD can understand. BTW, no implication that coolant "sits" in the radiator, since that would indicate a more serious problem. 
Oh, and if there's a shroud on the radiator, that is a tremendous help.
-----Original Message-----
From: John Grady <jkg@xxxxxxxxxxxxxxxxx>
To: 'Mark Souders' <mrs954@xxxxxxx>; ttibbie <ttibbie@xxxxxxxxxxx>; Chrysler300 <Chrysler300@xxxxxxxxxxxxxxx>
Sent: Thu, Apr 6, 2017 12:41 pm
Subject: RE: [Chrysler300] 300G Cooling System Over Heating..

I do not question at all your experience Mark, and it could have the exact same roots, but ideas that water sits a time in radiator to cool best are incorrect. The way to think of it is to get rid of the most heat, the whole radiator should be hot and at the same temperature—whatever that temp is!!…..otherwise some of the radiator face is not removing any heat, which obviously cannot be as good as all of it removing  heat. . The faster the water flows, (thermostat open) the more even the radiator face and the more heat it is taking away, as then all the radiator face is hard at work. Same inside the block. This idea of it takes time to cool ( Or heat) a car engine ,or “pick up heat” is widespread, so no criticism, 
Smokey Yunick started it with 3/8” aperture washers in small block Chevies, saying it gave time for the water to get hot inside, (higher temp coming out) and cooler in the radiator bottom ..and measurement of temps with and without the washers showed , YES, that was true. What was wrong was his thinking,---if he took out the washers all would be the same (lower) temp as intended (outlet temp drops a lot because  more heat has gone out!  Engine is still adding same heat as before, but outlet water is cooler=more heat went away. …. and the formerly hotter water at outlet would be everywhere cooler..what we came here to do right? Lower the temp? 
This instead of thermostats that had failed on him in races. . 
But what you describe could still be wrong pump, exactly right, but caused by cavitation. A too aggressive pump will cause suction (low pressure)  very much  suction, at the  bottom of radiator. Near the pump inlet , at lowest pressure the water might then boil at like 180 instead of 212 (opposite the action of a pressure cooker, or high pressure cap , they raise it). Low pressure drops boiling temp at pump inlet .If it cavitates,  as this is called , all the pump has to move then is water vapor (cool steam) and flow can slow way down. Note that on the highway your thermostat starts to close due to wind in radiator, restricting flow causing the pump to try harder to suck the water into the bottom…This is like gas line vapor lock, for same reasons. On hot days. 
I have a hydroelectric generating plant, we have the same problem if too much “draft tube suction”  which is the 7-8 foot drop  tube into the river after the hydro turbine…you want suction, it adds to power, but too much and relatively cool river water boils just under the turbine blade , and it is violent,  and damages the turbine blades (hard to believe but true—like water hammer in steam heat ---as “cool steam” violently condenses back to water with a big bang as the bubbles collapse .
Hope that helps..
PS , FYI Heat quantity is measured in BTU, not temp. 100 temp in air is obviously less total heat than 100 temp in a block of steel (try to cool both down!) A gallon of water at a temp holds so many BTU, higher temp = more BTU, yes, proportional , But moving two gallons moves twice as much BTU out with the two gallons . At any temp. 
Further, a  mind experiment: you have a very hot 1 foot cube block of steel…squirt with 1 gallon minute or 10 gallons a minute …which cools the block faster? But the one gallon a minute flow , running off, will be “hotter temp” but less heat moving, why it takes longer to cool the block. . 

From: Mark Souders [mailto:mrs954@xxxxxxx] 
Sent: Thursday, April 06, 2017 11:21 AM
To: jkg@xxxxxxxxxxxxxxxxx; ttibbie@xxxxxxxxxxx; Chrysler300@xxxxxxxxxxxxxxx
Subject: Re: [Chrysler300] 300G Cooling System Over Heating..


Many years ago, in a past life, I had a 67 Charger with a 383 4bbl with AC. I needed to replace my water pump, so I thought since it's a high performance car I should have a high performance water pump. I went to my local Napa store and bought a high flow pump. Worked nice until I took it out on the highway. It began to overheat, so I got off the highway and drove back home on a rural road, The temperature went back to normal. 

To make a long story short, I took off the high flow pump and replaced it with a regular OEM pump. The car worked flawlessly after that. The issue was, at highway speed, the high flow pump was flowing the coolant through the radiator too fast, and it didn't have enough time to cool when going through the radiator. During rural road and city street driving there was enough time for the coolant to cool down going through the radiator. And we all lived happily ever after.






-----Original Message-----
From: 'John Grady' jkg@xxxxxxxxxxxxxxxxx [Chrysler300] <Chrysler300-noreply@xxxxxxxxxxxxxxx>
To: ttibbie <ttibbie@xxxxxxxxxxx>; Chrysler300 <Chrysler300@xxxxxxxxxxxxxxx>
Sent: Thu, Apr 6, 2017 10:44 am
Subject: RE: [Chrysler300] 300G Cooling System Over Heating..


There is a slight chance you have a wrong water pump or pump housing..there are some problems with certain 440 pumps currently routinely sold for 413 replacements , where some kind of metal plate or spacer is inside the pump housing and sometimes not. I do not know all the details, but bottom line is any given housing and pump must be made for each other. Add to this the variation in AC pumps (impellor design ) or not. 


As I understand it, from memory,  a situation can happen where there is a gap behind the impellor to the casting, due to incorrect mix and match, so flow drops . Even if it fits bolts, it might be the wrong one. . Sorry for lack of specifics, it was long ago. 


Perhaps see if you have strong flow in the radiator at slightly off idle say 1500 rpm???  also if water is moving well, then  generally radiator is almost  same temp top to bottom ; if slow top gets a lot hotter. (IR temp gun) Also attempts to make the radiator look nice with shiny black paint are obviously 100% in the wrong direction. Painted fins cannot throw heat well. 


Although I have no personal experience, there is a co selling both pump parts claiming hi flows , “flow cool” or something, hi flow water pump ;  If it gets to that.. If marginal pump , would expect hot in traffic, OK on highway at higher RPM? 


Not sure, of course,  if this is valid for you, but had some problems like this in past years with 480” 440 in 57 Dodge, built from various parts.  ; overheats at idle, all new stuff!! 


From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On Behalf Of ttibbie@xxxxxxxxxxx [Chrysler300]
Sent: Thursday, April 06, 2017 9:29 AM
To: Chrysler300@xxxxxxxxxxxxxxx
Subject: [Chrysler300] 300G Cooling System Over Heating..


I live in south central Texas (San Antonio) I purchased my current 300G last April 2016. The cooling system with AC is new including radiators, hoses, fan etc are all in new condition.. I've installed a recovery tank but the I'm still having problems with over heating on days where the temperatures reach 90 plus. Any suggestions.         



[Non-text portions of this message have been removed]

Posted by: Mark Souders <mrs954@xxxxxxx>

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