temperature gauge

L

larry mallia

Junior Member
My temperature gauge is always at the "H". Do you guys have any suggestions? Does it require a ground? This is on a 1956 customline, with a 272 two barrel.
 
If I remember right, power to the gauge and the sender provides a variable ground. On a 56, they are 1 year only 12 volt King Seeley gauges. They rest at H on temp and E on the fuel. Is there power to the gauge and does it have the correct sender. They are matched sets, again, 1 year only. But the King Seeley’ were used for years on either 6v or 12 with a factory drop resistor.
 
Memory is a little fuzzy on this, but i remember something about testing the gauge. Take the wire off the sender. With the ignition on, ground the wire. If the gauge moves, then the gauge should be ok and the problem most likely is the sending unit.


Regarding the sending unit - if you buy a new one, ask to make sure that it is compatible with the stock gauge
 
paul2748 said:
Memory is a little fuzzy on this, but i remember something about testing the gauge. Take the wire off the sender. With the ignition on, ground the wire. If the gauge moves, then the gauge should be ok and the problem most likely is the sending unit.

Regarding the sending unit - if you buy a new one, ask to make sure that it is compatible with the stock gauge
Click to expand...
If the wire from the gauge to the sensor has missing insulation & is shorted to the body of the car, or is broken / 'open' somewhere, the gauge won't work by grounding the end of the wire at the sensor.

Original '56 gauge parts are one-year-only, made to work on full 12v. ('57 was the first year they used a voltage reducer.)
New replacement sensors are likely made 'off-shore' and aren't made the same way as the originals. They may not work as well as described or expected.
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Is the wire from the sender connected to the tab on the gauge? The gauge always reads "H" when the ignition is off.
 
Hello Way back a fella put a how to do in TB magazine about temp sending units. He took it apart and filed little points to get it working again. There are numbers stamped on the ones I have looked at. I assume they mean what temps will be at max temps. I don't remember for sure but sender is a on and off signal trigger by a bimetal strip with points. Think shop manual has testing procedure.
 
dmsfrr said:
. . . New replacement sensors are likely made 'off-shore' and aren't made the same way as the originals..
Click to expand...
Before '57 the King-Seely brand gauges operated with heat sensitive bi-metal switching contacts in the sensor. See the attached illustration.
Starting in model year '57 oem sensors were upgraded to variable resistors, not compatible with prior year parts.
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Might also be simply the wrong sending unit. My 292 had the wrong one installed and so when cold It was literally in the middle of the gauge, and then as it warmed up would always be pegged to the far right. Chalk this up to one or two decade old replacement back before the Internet and parts were readily available. I purchased the correct sending unit from Ecklers or Dennis Carpenter around 2020 and it worked perfectly ever since.
 
Larry, guessing the problem is not the sensor!!! So, have you checked the wiring from the sensor to the gauge?
 
Isn't a temp gauge a big ohm meter?

Did it ever work correctly? Where the wire goes through the firewall, is the insulation cut?
 
The King Seeley systems always pegged on H with the key off. With key on before 1st start, it should drop down to C. It may not be getting power to the circuit. That could be a bad sender or a bad indicator. With full 12-volts and no sender in the mix, it should go to cold.

King Seeley designs were based on pulsating current by bi-metallic switching. They would work with a bi-metallic pulse current voltage regulator but then you have two switches in the circuit so it makes the indication a bit sloppy.
 
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