temperature sending unit

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sevenmilebridge
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temperature sending unit

Post by sevenmilebridge »

Has anyone had a problem with a sending unit that sends the wrong voltage to the the temperature guage? Makes the guage read hot when its at normal temps?
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keith0alan
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Re: temperature sending unit

Post by keith0alan »

Yes, the senders seem to read high as they age. You can check the actual temp with an IR or candy thermometer.
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AidanDawn2000
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Re: temperature sending unit

Post by AidanDawn2000 »

Mine reads high. Gauge is is pegged when temp at elbow is only around 210.
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keith0alan
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Re: temperature sending unit

Post by keith0alan »

You can calibrate it by putting a resistor in series with the sender. Get a 100 ohm variable resistor and put in line with the sender. Adjust to correct the gauge. Then measure the adjustable resistor and install a fixed one in it's place. However, if your gas gauge is also reading high then check your instrument voltage regulator.
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sevenmilebridge
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Re: temperature sending unit

Post by sevenmilebridge »

I checked the water temp with a meat thermometer and it was about 70 degrees off. Its a new sending unit so the resistor sounds like the way to go to get it exact. Thanks
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Nissanman
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Re: temperature sending unit

Post by Nissanman »

The gauge in my '65 1500 is actually adjustable, I don't know about later models.
There is a small hole in the rear of the gauge case and you can move the mechanism to fine tune the reading to that measured by a reliable source e.g. a thermo-couple device.
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Randalla
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Re: temperature sending unit

Post by Randalla »

I'm having the same issue with my 67 1/2 1600. Gauge seems to be working but pegs the needle in a relatively short time. My IR scanner shows the actual temperature to be about 180 degrees. I'm curious to know if anyone knows if the factory gauge in my car has an adjustment like Nissanman's. If so, I'll pull it out and see if I can calibrate it. Otherwise I'll try the resistor. It's more than a little disconcerting to see the needle pegged while driving.
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Nissanman
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Re: temperature sending unit

Post by Nissanman »

When you view the rear of the gauge case, look for a plug or a round hole ~8mm diam.
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Randalla
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Re: temperature sending unit

Post by Randalla »

Is adjustment with a small screw driver, an allen wrench or???
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Nissanman
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Re: temperature sending unit

Post by Nissanman »

Mine was a slide type device which you could move left and right with a small screwdriver.
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Randalla
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Re: temperature sending unit

Post by Randalla »

Cool. Out it comes tomorrow.
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Nissanman
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Re: temperature sending unit

Post by Nissanman »

Good luck! Have a good look at the rear case and if it has a hole, use a decent magnifying glass to inspect the interior.
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steve_car
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Re: temperature sending unit

Post by steve_car »

The 66-67 temp gauge does have an adjustment wheel. Also, the fuel and oil gauges have one.
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Re: temperature sending unit

Post by Randalla »

Steve, good to know. My fuel gauge works, but has a very small range. When it's full the gauge sits at 3/4 and when it's empty it shows 1/4 full. Do you know whether this is a gauge calibration issue or a sending unit issue?
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AC77
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Re: temperature sending unit

Post by AC77 »

steve_car wrote:The 66-67 temp gauge does have an adjustment wheel. Also, the fuel and oil gauges have one.
That is good to know. Thanks Steve!
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