Electrical 1985 GT

Ethan Keirn · Feb 6, 2019

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.

Rdub6 · Feb 6, 2019

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.

Ethan Keirn · Feb 7, 2019

Rdub6 said:
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.

I replaced the sender, the little one right behind the distributor.

Rdub6 · Feb 7, 2019

https://lmr.com/item/LRS-12648A/83-95-Ford-Mustang-50L-Coolant-Temperature-Sensor

Here is what the sensor looks like. It’s on passenger side of manifold on my 86. Not sure if it’s same spot on the carbuated 85.

General karthief · Feb 7, 2019

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 · Feb 7, 2019

General karthief said:
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 · Feb 7, 2019

Rdub6 said:
https://lmr.com/item/LRS-12648A/83-95-Ford-Mustang-50L-Coolant-Temperature-Sensor

Here is what the sensor looks like. It’s on passenger side of manifold on my 86. Not sure if it’s same spot on the carbuated 85.

Will having a new sending unit and an old sensor cause problems?

Rdub6 · Feb 7, 2019

Ethan Keirn said:
Will having a new sending unit and an old sensor cause problems?

If the gauge wasn’t working at all, and now is, the sender was bad. But the sensor may be bad as well giving you false readings.

Ethan Keirn · Feb 7, 2019

Just took readings from the sending unit and around the manifold and it was 170-180 F

Ethan Keirn · Feb 7, 2019

General karthief said:
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

Electrical 1985 GT

Ethan Keirn

Member

Rdub6

So while I wait to figure out my rear end issues

Ethan Keirn

Member

Rdub6

So while I wait to figure out my rear end issues

General karthief

wonder how much it would cost to ship you a pair

Ethan Keirn

Member

Ethan Keirn

Member

Rdub6

So while I wait to figure out my rear end issues

Ethan Keirn

Member

Ethan Keirn

Member

Similar threads

Electrical 1985 GT

Member

So while I wait to figure out my rear end issues

Member

So while I wait to figure out my rear end issues

wonder how much it would cost to ship you a pair

Member

Member

So while I wait to figure out my rear end issues

Member

Member

Similar threads

Privacy & Transparency

Privacy & Transparency