Cold/Hot lights

[live4theking]

I've looked through my manual for my 68 NYer, but I've been unable to find the temps that operate the cold and hot lights.

 

[CBODY67]

I have never seen those specs in the FSM, either. Cold probably goes out after abt 100*F and the hot comes on at abt 260*F?

 

[live4theking]

Wow, 260° that seems to be really hot.

 

[CBODY67]

260*F is the approx boiling point of water with 15psi pressure, as in the cooling system. Compared to the normal 212*F at normal atmospheric pressure.

On our '66 Newport factory a/c car, we never saw the HOT light come on, period. Good radiator, good hoses, no leaks or seeps, functioning fan clutch, tune-up specs good, good radiator cap, too.

The temps I mentioned are just my speculation, as to how I might stage things. Perhaps there is something better hidden in the Chrysler MasterTech series, somewhere?

Back then, our Gulf service station guy, who was a former Chrysler light-line tech, said that unless a Chrysler cooling system was having an issue (maintenance or failing components) they never had "heat" issues. I trusted him in that statement as it mirrored our experiences on the '66 Newport and later on my '70 Monaco 383 factory a/c car. FWIW

CBODY67

 

[sprice]

I have never seen those specs in the FSM, either. Cold probably goes out after abt 100*F and the hod comes on at abt 260*F?

Or perhaps the same temp for when auto-temp kicks in which I think is 125 degrees? Either way, I suspect within this range for the "cold" light.

 

[CBODY67]

Seems like when the "cold" light goes out, the heater can work? I'm thinking the low mark on most in-dash temp gauges starts at 100*F, so 125*F would make sense.

CBODY67

 

[Gerald Morris]

Seems like when the "cold" light goes out, the heater can work? I'm thinking the low mark on most in-dash temp gauges starts at 100*F, so 125*F would make sense.

CBODY67

According to O'Reilly Auto Parts, the SR-15 temperature switch switches the "Cold" OFF at 103 Fahrenheit, and the "Hot" ON between 246-263F. That flaky 1968 383 I got with Gertrude made the red light come on several times, before I pulled it out, and installed the reliable 1965-66 engine still running strong in it.

 

[live4theking]

Thanks for the input guys.

 

[440C-Body68]

I've looked through my manual for my 68 NYer, but I've been unable to find the temps that operate the cold and hot lights.

I replaced the hot / cold sensor (switch) on my '68 New Yorker 440 this past November with an unused NOS part from a fellow on Ebay. I couldn't find any spec for those temperatures in my 1968 Chrysler shop manual. I too was interested in knowing what those temperatures are so I tested the cold set point and found it to close the switch at 128 DegF (very consistently) and open back up between 121 and 124 DegF.

I used two Fluke multi-meters, one measuring resistance to observe whether the switch was open or closed and the other connected to a very high accuracy temperature probe (-/+ 0.4%) to measure the temperature of water from our kitchen faucet. Since our on-demand water heater can be set to 145 degrees, I set it to that and mixed cold and hot water from the faucet starting at 100 degrees, slowly closing off the cold faucet while measuring the water temperature until the switch closed. My guess is the switch was factory spec'd at 130 degrees. If it seems I might be a retired geeky engineer, there's good reason for that. All I know is my wife sees me at the kitchen sink with "devices" and wires and running water and just rolls her eyes at me.

I had no real good way to test the hot set point but I would think you'd want to know when engine temperature exceeded around 245 degrees, giving you a 20 degree warning before the water in a cooling system with 50 /50 coolant solution and a 15 PSI cap started to boil.

Hope this was helpful.

 

[Gerald Morris]

I had no real good way to test the hot set point but I would think you'd want to know when engine temperature exceeded around 245 degrees, giving you a 20 degree warning before the water in a cooling system with 50 /50 coolant solution and a 15 PSI cap started to boil.

Hope this was helpful.

Put some canola oil in a skillet and go get a cooking thermometer. Use the Fluke T probe as a second instrument. I know Fluke has a high reputation for precision, but I'd still trust an old school mercury thermometer more, especially one made from the Mercury Era, before Big Mother started grabbing all the Good **** for our "protection."