These are like gas gauges, very inaccurate and even if gauge is attempted to be calibrated ,unlike computer equipped cars, the analog sender end is not ; That said, these are often messed with, and may be way out , why JC can correct outliers ( any adjustment will be turned (John’s law, aka “golden screwdriver” ) and the gauges have two..do not touch them ,unless you know for sure what you are doing, and have correct test signal) ---only a real reading with infra red remote(probably best) or thermometer will tell you numerically about what the gauge is really telling you, no matter where on dial that is ; getting a conceptual data point just over 200 is good, as water thermostat will open and close to keep engine at its setting, 180 or 190; once it cannot do that (it is open all the time, cannot keep up with heat ) temp will go over 200-205, ---or more, on hot day, A/C on; that is what you need to know . Also a low pressure relief cap and overflow bottle (latter, if added) will become active , in the 220’s, telling you it is stressed ; with 180 or 190 (or 160!) thermostats, and all working, on a cool day , the pointer inside will point to that “in regulation” desired temp, once warmed up all the way.,.. a good quick way to tell when things are about right; a more upscale reading indicates it is over thermostat setting, which is somewhat normal when stressed, but if that happens on a cool day, or unexplained, problems coming .
I had some problems with correctly fitting relief caps on these cars, as a true relief cap needs to seal to outer/upper radiator lip as well as to inner radiator neck where spring pushes it down. Some of the originals have a sort of springy brass plate for upper /outer seal, as it is only to keep water from getting out at cap edge faster than drain tube open to ground can get rid of it ; with no or poor seal there , overflow bottle water will not get sucked back in by vacuum when cool. New caps with upper seal seem not to fit upper ring of OEM radiators quite right---doubt it was designed for those. Although they clip on OK.
You can also see the following action on some cars; as it warms up it usually overshoots the stable point by 5% or so, and then comes back as thermostat opens and slug of cool water goes around ,the first time, then it goes back to stable point . A lot of info for you, in that action…..Or when climbing long hills.
You can sort of get used to where it sits, that is your normal, why normal bar is long. If it starts going more, something is behind that, unless very hot day and/or A/C on.
My .03…………..
john
From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On Behalf Of Tony Bevacqua
Sent: Monday, May 05, 2014 10:05 AM
To: 'Charlie V'; 'rinandal'; chrysler300@xxxxxxxxxxxxxxx
Subject: [Chrysler300] temperature gauge actual temperatures
FYI, I found my G having a VERY high read with no boiling nor overflow, etc., so Jeff Carter suggested that he send me a recently calibrated one to put in, which I did. I sent him mine and kept his because it brought the temps down to normal readings. You might consider this way, especially if you want the correct gauge for your year.
Tony
From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On Behalf Of Charlie V
Sent: Monday, May 05, 2014 2:53 AM
To: rinandal; chrysler300@xxxxxxxxxxxxxxx
Subject: Re: [Chrysler300] temperature gauge actual temperatures
Hi Van,
I would say that in the middle is just right and over there on the side of " H " is too HOT.
But not necessarily so. On my 62 300 Sport Convertible the gauge is always on the " H " side. I installed another temp gauge and that show the engine running around 185 degrees.
Charlie Valentine
From: rinandal <rinandvan@xxxxxxx>
To: chrysler300@xxxxxxxxxxxxxxx
Sent: Friday, May 2, 2014 6:03 PM
Subject: [Chrysler300] temperature gauge actual temperatures
Hi all,
Heat just came on in southern CA. Which brings me to my question . On my 1964 K there are no numbers on the temperature gauge. So if all is stock and in good working order for the sake of this question: What temperature does the little "overheat" section on the right hand(hot) side of the gauge represent?
Thanks,
Van
[Non-text portions of this message have been removed]