Electrical 1985 GT

Ethan Keirn

Member
May 11, 2017
57
0
6
20
Tidewater Virginia
Hello, recently bought an 85 gt and love it, but shortly after purchase the temp gauge stopped working so I swapped out the temp switch with a new duralast one from autozone. Well the gauge started working again but it was reading way high, like too high, around the A or L in NORMAL. I swapped out the thermostat and rad cap, and even bought a laser thermometer to measure the block and heads which read around 170-190F which seems normal enough to me, any advice would be appreciated.
 
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Rdub6

Mustang Master
Dec 29, 2017
1,188
874
123
Long Island, NY
Did you change the sender or the sensor? One just sends info to the gauge, the other talks to the computer to help the motor run properly.
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
15,578
4,936
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polk county florida
The gauges in these cars are known for being inaccurate, teflon tape will skew the resistance to ground making the gauge read wrong. I have a list of resistance values someplace I got from an aftermarket gauge company because the sender I got was reading high, I tested 3 parts store senders and all registered different values at the same temperature so the gauge would read different between each sender, also there could be a air bubble around the bulb that could skew the reading although that usually result in a low or no reading.
Did you take a laser reading at the sender? If so what was it? Keeping in mind that metal/aluminum will be warmer than the coolant.
 

Ethan Keirn

Member
May 11, 2017
57
0
6
20
Tidewater Virginia
The gauges in these cars are known for being inaccurate, teflon tape will skew the resistance to ground making the gauge read wrong. I have a list of resistance values someplace I got from an aftermarket gauge company because the sender I got was reading high, I tested 3 parts store senders and all registered different values at the same temperature so the gauge would read different between each sender, also there could be a air bubble around the bulb that could skew the reading although that usually result in a low or no reading.
Did you take a laser reading at the sender? If so what was it? Keeping in mind that metal/aluminum will be warmer than the coolant.
No I just took temp readings from the block and heads, but tonight I'll check the temp at the sender
 

Ethan Keirn

Member
May 11, 2017
57
0
6
20
Tidewater Virginia
The gauges in these cars are known for being inaccurate, teflon tape will skew the resistance to ground making the gauge read wrong. I have a list of resistance values someplace I got from an aftermarket gauge company because the sender I got was reading high, I tested 3 parts store senders and all registered different values at the same temperature so the gauge would read different between each sender, also there could be a air bubble around the bulb that could skew the reading although that usually result in a low or no reading.
Did you take a laser reading at the sender? If so what was it? Keeping in mind that metal/aluminum will be warmer than the coolant.
I just took readings at the temp sender and on the aluminum manifold around it and I got 170-180F with a laser thermometer