Temperature gauge inaccurate

[JWF]

This is my first post here as I am new to the Pontiac world. I've come over from the Corvette world. I just purchased a 1970 formula 400 and absolutely love it, here's my question. I noticed the temperature gauge was not working so first because it was cheap I put in a sender unit , no change. Checked the wiring and all was in order. So I ordered and installed the gauge in the cluster and replaced that. It now works but I notice when it reads 100 degrees when I check the temperature at the sender unit with a infrared gun it is running 160 degrees which is fine but yet my gauge is reading 100 degrees. New sender , new gauge and wiring is good and it has a 160 degree thermostat in it which is where the engine is running. Any thought as to why the gauge would be 60 degrees off ?
Thanks guy !

 

[melsg5]

Just like in the Corvette world, I have a 69, the sender may not be correctly calibrated.
Where did you buy the sender?
Did you put anything on the threads of the sender?

 

[G-742334]

Just like in the Corvette world, I have a 69, the sender may not be correctly calibrated.
Where did you buy the sender?
Did you put anything on the threads of the sender?

The sender was purchased from O'Reilys……..The sender had what appeared to be a white coating on the threads when purchased which I liked because the one I replaced had nothing and it was slightly leaking. How do you calibrate a temperature sensor ?

 

[melsg5]

You checked to make sure they didnt sell you a sender for an idiot light?
Did you measure the resistance of the old one and the new one?
I would replace it with this one and the threads have to be partially bare in order to have a good ground.

Temperature Sending Unit

-original 1/2 x 14 N.P.T.F.-, with factory gauges/Rally Gauges (correct resistance and connection, produces accurate gauge display)

www.lectriclimited.com

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[G-398393]

You checked to make sure they didnt sell you a sender for an idiot light?
Did you measure the resistance of the old one and the new one?
I would replace it with this one and the threads have to be partially bare in order to have a good ground.

Temperature Sending Unit

-original 1/2 x 14 N.P.T.F.-, with factory gauges/Rally Gauges (correct resistance and connection, produces accurate gauge display)

www.lectriclimited.com

yes it is for a gauge...….don't recall the resistance values but I did observe it changing as I fooled it with a heat gun and watched as it went from cold to hot. the sender is fully grounded to the manifold so I'm not concerned with the sealer on the threads. Thank you for your reply