RE: [Chrysler300] 64 413 AC radiator cap.

Well, I don’t know who Smokey Yunick is, but all I’m saying is when I changed the high flow pump to a regular pump, all my overheating issues went away. Just sayin’….

Mark

From: John Grady [mailto:jkg@xxxxxxxxxxxxxxxxx]
Sent: Tuesday, June 30, 2015 12:16 PM
To: Mark Souders
Cc: Ryan Hill; Dave Dumais; Chrysler 300 List
Subject: Re: [Chrysler300] 64 413 AC radiator cap.

Hi ---some help , hopefully --first , it cannot flow too fast to cool . That started w Smokey Yunick .. A trick by him ---he hoped others he raced would slow water flow with restrictors he told you how to make ( washers with holes, in SBC ) . All BS , ---he smiled . Just not true in engineering sense . He knew that . Too long to get into why , But widespread belief . Opposite is truth .

But there are apparently two block front castings and depth of water pump impellor into casting on various B blocks . Do not know details and some kind of filler , water guide or spacer plate is supposed to be used w some pumps / castings . Get wrong pump / casting / plate combo , the gap space behind or around impellor causes low flow . Why changing pump can fix it . Hi flow pump probably designed for 440 , think it has the different casting space . Wish i had specifics on this ! Memory ....

Psi of cap does not enter it until over 212 if rest ok . That rarely happens in a good car ( climbing long hill w air ?-- needle higher than usual 180 , normal ) . No boil, is = essentially no pressure . If it boils --= over 212, hi psi gives you more room , say to 240 deg . (Stuck in traffic 110 day ) But can pop hoses , heater cores , heater valves and freeze plugs . I use 7 psi now . It opens without drama out overflow if things get to like 220 . No big mess from sudden hi temp cooling puke / which then instantly flashes coolant to very hot very dangerous steam . Can boil locally inside at exhaust valve yet be 190 circulating . ( understand --high load / motor home / tow issues) .

Thermo temp rating --it opens / closes cycles , and if big good radiator it stays at that temp . 160 said to be too cold for clean engine . You want water vapor out of engine . (Hot ) But will go to 190 with either thermo if it needs that to cool enough ( cool enough = BTU thrown away, is proportional to temp of good or bad radiator over the air .. Bad = much higher water temp , for same BTU . ) So 160 thermo does not fix overheating . Radiator not throwing off the heat , is the issue , if all else ok . Often tubes are lined with junk inside . Or someone painted radiator ( beautiful heavy paint greatly impedes cooling) . Or fins corroded away from tubes ..( old press fit ) And yes , bugs -- behind or in ac fins

I think old radiator is the issue --usually ---or too small a rating ( wrong or old replacement radiator ) . Unless fan clutch . I am not sure if all 300,s had fan shroud but that really helps . Sometimes it gets tossed . .. Long ago

Air can get trapped in heater but have never seen in block once revvd once . One fast drive fixes it . Inc heater ---if heat valve open . Gauges often wrong/inaccurate ..senders vary . Gauge itself messed with . Lower hose must be stiff , or wire inside , not flappy or creased . Will suck shut w high flow .
My .02 ..

John

( PS --or auugh , please no --head gasket or crack---then cap opens with coolant still under 212, hoses get hard , bubbles --or better , pressure spike in radiator when rev'd , steam / drip out one exhaust , skipping , coolant loss without leak . rad pressure tester is cheap --a good thing . )
Sent from my iPhone

On Jun 30, 2015, at 4:33 PM, 'Mark Souders' MRS954@xxxxxxx [Chrysler300] <Chrysler300-noreply@xxxxxxxxxxxxxxx> wrote:

Something else to consider, I once had a 67 Charger, I replaced the radiator, thermostat, and water pump. I thought I’d put on a high volume pump since it’s a high performance 383 (with AC). When I drove it down the interstate, it would overheat, but would not overheat while driving on rural roads or city streets. I eventually consulted a mechanic, who told me that at highway speed, the high volume water pump is flowing the water through the radiator too fast, and it didn’t have enough time to get cooled by the air flow through the fins. I replaced the high volume pump with a standard pump, and my problem was solved.

Happy Moparing,
Mark

From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On Behalf Of Ryan Hill ryan_hillc300@xxxxxxxxxxx [Chrysler300]
Sent: Tuesday, June 30, 2015 1:25 AM
To: Dave Dumais; Chrysler 300 List
Subject: RE: [Chrysler300] 64 413 AC radiator cap.

Just my two cents. Not to discount the comments regarding the rad, they're certainly valid and a capable radiator is imperative to keeping the engine and transmission cool.

Also though, a newly built engine will generally run a little hot until it's broken in and tuned correctly. How lean are you running with your carb settings? Are you sure your timing is dialled in? Why are you running a 160 thermostat? Isn't a 180 the recommended temp? Are you sure there's no air trapped in your system?

Ryan Hill
To: chrysler300@xxxxxxxxxxxxxxx
From: Chrysler300-noreply@xxxxxxxxxxxxxxx
Date: Tue, 30 Jun 2015 00:25:19 +0000
Subject: [Chrysler300] 64 413 AC radiator cap.

After installing the new 4 core with shroud, 7 blade fan and 160 thermo, the 300 runs hot, close to the upper limit.
Have not driven it yet, only raised the idle to 2k, and the gauge dropped a bit to the left.

The block is a new build with 200 or less miles, clean on the inside.
The cap is a 13 #. No leaks. runs hot.

Any thing look incorrect ?

Thanks,
Dave D.