I have yet another question, about my coolant sensor

My coolant gauge in my 71 cuda 440 reads about 3/4 or more when fully warmed up....Shouldn't it read towards the bottom just pass the first line, I have replace the gauge twice, I have replaced the sender twice, and I have replaced the limiter, my challenger reads about the first line..and before you ask I have checked with a temp led gauge reading about 181 degress at the water pump...

Both are the same temp, 181 for their respective gauge readings?

Kevin

the temp is perfect, but why does one read at the low line and the other read at the high line, with the same temp being 180

My 70 cuda reads just under half way at 180.

it may be a matter of mix and match to get it to read where you want.

based on voltage that gets to the gauge due to resistance.

5 volts assuming your other gauges read correctly

10 to 73 or 12 to 78 ohms for the sending unit. same as the gas tank one, so if you have a spare one of those you can test the gauge vs boiling water to check.

There is going to be some fudge factor in the sending and gauge units.
you could add some resistance in the line to make it read what you want, and then if it moves past that you know you are in trouble vs what it currently shows.

Could be poor contact at bulkhead connector or gauge out of calibration. Another source of resistance is where the wire connects to the circuit board
Jim

Thanks guys, all the wiring is new( yes I know that dont mean squat) I agree with Andrew on the resistance, I noticed 68 uses a different sender, does and one know the difference in resistance , are and which way to go on a resister. hard to believe everything is out of whack, just bothers me to see the gauge that high, but knowing its not running hot,and nothing is working..

Gauges are adjustable...

There is a 15% +/- of tolerance for the resistance output of a sensor. Also for the posted discrepancies, what brand was the sensor?
Aftermarket sensors can/will vary alot, that's why we always try to use an OE sensor.

Just my $0.02...

[quote=Jim_Lusk]Gauges are adjustable... [/quote
I did not know that ... Napa sender 2 of them... and 2 gauges

test them and find out

Did you try a used sender? I had problems years ago, replacement senders I was finding all had a different length of probe then stock and didn't read right. I stuck a used one in from a spare intake I had kicking around and went back to working properly again.