C1 temperature sensor?

[Dave Christensen]

Does anyone know what the resistance of the temperature sensor on a 56 should be at some temperature?

Are there different sensors, with different resistances, for different years?

I ran my newly rebuilt engine for a few minutes and the temp. gauge went to 220 degrees. I have a new radiator, hoses, thermostat, and temp. sensor. I put a thermometer in the radiator and the water temp. was ~155 degrees. The temp. sensor had a resistance of 120 ohms. I put the sensor in 180 degree water and it measured 120 ohms which leads me to believe that my sensor is not right for the gauge.

I bought the sensor from Zip Products. It was advertised as correct for my 56. But, I have learned not to rely on that, especially for a 56.

Any suggestions?

thanks
Dave Christensen

[Joe L.]

Re: C1 temperature sensor?

Dave------

I've heard of a lot of folks that have had problems with the replacement sending unit currently supplied by GM, GM #12334869, and this is very likely what Zip sold you.

The original sending unit used on your car was GM #1513130. This is a pin type connector terminal sending unit (I used to think that it was a button-type but I just researched this the other day and learned I was wrong). This part was discontinued in 1967 and replaced by GM #6400759. Either of the previously referenced sending units is very hard to find today.

However, GM later replaced the 6400759 sending unit with a button-type terminal sending unit, GM #1513321, which was available for many years until it was replaced several years ago by the 12334869. The 1513321 sending unit will work well for your application and is calibrated properly. Finding one of these is not easy, but it's a lot easier than finding an original 1513130 or 6400759.

Also, I think that you can calibrate your existing sender by adding in-line resistance of the proper value. You might want to e-mail Fred Oliva for instructions on how to do this or search the archives.

[Dave Christensen]

Re: C1 temperature sensor?

Joe,
Thank for your help. I searched the Restorer archives and found that my sensor should not work with my gauge.

Do you have any contact information for Fred Olivia?

thanks
Dave Christensen

[Ed Jennings]

Re: C1 temperature sensor?

Dave, Not sure about earlier C1's but on 58-62 models the senders that seem to work have a resistance of about 700 ohms @ ambient temp. (70 deg or so). I and a couple of others have had real good success with senders from Autozone. These are the button style which isn't correct for your car. Don't know if they carry the pin style or not. You might ask. The later ones are identical in appearance to the Delco units except for the marking. They simply read "12V". If you are more interested in function than form, you might check this out.
Installing a resistor in the circuit to calibrate the sender will only calibrate it in one fairly narrow range. However, if you are after strict originality, this may be the only option.

[James F.]

Re: C1 temperature sensor?

Dave,
The resistance should be as close to 700 ohms as you can find. The wire at the sensor should fit the pin type only on your '56. The button type head sensor can be machined down to a "pin" profile. Regards,

[Richard E.]

Re: C1 temperature sensor?

Dave - At one time Fred Oliva was calibrating original temp senders by setting a resistor within the element itself. Fred is at Vintage Automotive Research, Coral Springs, FL,305-755-1161. (foliva@gate.net)

[Bob Babcock]

Re: C1 temperature sensor?

On my 60 Corvette, I put a resister in series and it seems to be fairly accurate. As I recall the value of the resister is 16 or 18 ohms.