Coolant temp sender ohm range

[dan juhasz]

As far as I know the range for the coolant temp sender for a 69 Charger is 10 to 73. 73 being cold and 10 bring 250 degrees. I’ve bought numerous ones and none fall into those specs and of course the gauge either never comes off cold or hovers at 250 on the gauge. Does anyone sell a proper sender?

 

[dadsbee]

Sender at 68f room temp should read in the ball park of 360 ohms. 73 would be bottom of the actual gauge scale and 10 at full gauge.

 

[dan juhasz]

Sender at 68f room temp should read in the ball park of 360 ohms. 73 would be bottom of the actual gauge scale and 10 at full gauge.

isn’t 73 and 10 the range in ohms of the sender itself ? Where does 360 ohms fit in, I’m not following?

 

[dadsbee]

NO, that is the ohm range to make the gauge read... from what 160f to 260? On a bench at room temp, somewhere around 360.

 

[451Mopar]

Here is some notes I have from when I calibrated my 1969 Rally dash:
At 120 degrees water temp (first mark on gauge), the sending unit (unloaded, connected to DMM) read 84.3 Ohms.
To get the same first mark position on the gauge with a 5-volt power supply took 62 Ohms of resistance and drew 62.1 mA of current.
At 150 degrees water temp (about 1/2 way between first mark and second mark) the sender showed 49.5 Ohms unloaded.
To get same position with 5v took 33 Ohms and current was 98.8 mA.
At 170 (second mark on gauge) sender unloaded was 37.5 Ohms
Loaded @ 5 volts took 22 Ohms and 119.7 mA
At 180 (needle straight up) 30.4 Ohms unloaded sender reading.
Loaded @ 5 volts 20 Ohms and 130.0 mA
I could not check sender resistance above boiling point (not pressurized when testing)
The next high temp mark, I think might be about 225-230? loaded @ 5 volts took 13 Ohms and 160 mA
Full scale (I think 240?) took 12 Ohms and 163 mA

Note that 5 volts was used for the Instrument Voltage Regulator (IVR) because I converted the factory one to solid state.

 

[steve340]

I bought the gauge style but I cannot remember the part number from Year One.
Works correctly.
Use sealer not thread tape.

 

[Dana67Dart]

The values in Red diamonds on the graph are extrapolated based on the curve I don't have a way to get the water above 210 deg

The Red Squares are the gauge readings 0 = cold, 25 = 1/4 scale, 50= 1/2 scale etc

My thermostat is 180 deg and my gauge sits at between 1/4 and 1/2, so in the 190 to 215 deg range