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I’m stuck on a problem with my temperature sending unit. I have a 1964 327 V8 in my 1957 Chevy 1/2 ton. I bought a sending unit for a 1957 V8 that fits in the intake manifold. My logic was that the sending unit should be matched to the 1957 gauge.
I tested my gauge by disconnecting the sender wire at the sending unit and grounding it to the negative battery post and turning on the ignition switch. The gauge pegged on the hot side. With the sending unit wire attached, the gauge needle jumps slightly toward hot when I turn on the ignition switch. However, when I run the engine, the temp gauge doesn’t register any change above the lowest level. I checked the temps around the thermostat housing with my IR gun and I’m getting in the mid 180s.
My next step will be to see if the sending unit is properly grounded. I’m wondering though if I have the wrong sending unit.
I have read several old posts about this, but I haven’t seen the answer there.
Any ideas?
Thank you,
Larry

I was suspicious of the temperature gage in my '57. I had to repair the gage when I first bought the truck, one of the rivets that hold the gage face had pulled out and broke one of the hair-fine wires. I made the repair but wondered about the accuracy. Recently I added a triple gage set of temp, oil pressure, volts under the dash, to help with easing my suspicions about all of the gages. The original gage in the instrument panel never registered above 1/3rd although it did seem to work with changing temp. Now with the AutoMeter triple gages I saw that the engine was not getting up to 180 degrees, I replaced the thermostat with another new 180 and both temperature gages are in agreement. My 283 also has the sensor threaded into the intake manifold. I thought I would tell my story just to give you more info, I think I would make sure the current thermostat is holding at 180 and also try a different sender.

Thank you. I have been thinking of adding the under dash gauges too.

I keep an eye on my local Craigslist, I found the triple AutoMeter gages and a Sun SuperTach with the steering column mount all for $125. Nice to know what is happening under the hood. And it was a good excuse to take the Harley for a ride to pick them up.

The temp senders that you see floating around, while they will physically install, they are not the correct resistance. Try the version sold by Lectric Limited.

https://www.lectriclimited.com/cata...s/temperature-sending-unit/category/734/

Thank you!