Temp gauge testing confirmation

[Gonzo1970]

Replaced the sender, and it started working again.

However, instead of reading the "normal" 190 or so, it reads 240... about 50 deg high.

I know its working because you can watch it raise in temp, then watch the temps drop significantly when the thermostat opens.

This drop in temp used to happen at around 200 (Guessing 185 Therm in it). Now this happens at 240.

I'm thinking the sender is bad.. But at least its reading Something, albeit 50 degrees high.

Think Ill go grab another.


-Gonz

 

[pontiacgp]

What model is your car, which engine/cluster? These details can make a huge difference in determining the cause of your issue. And teflon tape does not affect the operation of the sensor/gauge.

"Classic Instruments temperature and oil pressure senders require a ground which is made through the threads to the engine. Using a lot of sealer or Teflon tape on the threads of the sender will cause a bad or no ground connection. This will make the gauge read lower or not at all. "

Top Ways to Mess up Your Gauges - Goodguys Hot News

We all have a set of gauges right in front of us every time we get into our hot rods. Modern gauges are generally quite reliable but like many other systems, there are ways we can mess up their installation. We have seen guys chase nonexistent overheating or low oil pressure problems simply...

www.good-guys.com

 

[pontiacgp]

Replaced the sender, and it started working again.

However, instead of reading the "normal" 190 or so, it reads 240... about 50 deg high.

I know its working because you can watch it raise in temp, then watch the temps drop significantly when the thermostat opens.

This drop in temp used to happen at around 200 (Guessing 185 Therm in it). Now this happens at 240.

I'm thinking the sender is bad.. But at least its reading Something, albeit 50 degrees high.

Think Ill go grab another.


-Gonz

test it with your multimeter set on OHMs..

 

[Gonzo1970]

Awesome chart. Will do after work, unless I fall asleep

-Gonz

 

[Gonzo1970]

Can't find my ohm meter. I blame the wife.

I did, however, have a Laser/Infrared temp gun.

Sensor temp 194. Gauge showing 235.

So, at least I know its not overheating.. Now where did she put that multimeter...

-Gonz

 

[pontiacgp]

Can't find my ohm meter. I blame the wife.

I did, however, have a Laser/Infrared temp gun.

Sensor temp 194. Gauge showing 235.

So, at least I know its not overheating.. Now where did she put that multimeter...

-Gonz

it's cheaper to replace the multi meter than the wife, don't ask me how I know this.....

 

[87National]

"Classic Instruments temperature and oil pressure senders require a ground which is made through the threads to the engine. Using a lot of sealer or Teflon tape on the threads of the sender will cause a bad or no ground connection. This will make the gauge read lower or not at all. "

I've used teflon tape for years on temp senders and never had an issue. The tips of the threads cut right through the tape providing ground to the sender.

I suppose if you screwed a sender in finger right you would not have an adequate ground......but that would be the least of your worries because you would have coolant leaking everywhere.

 

[Gonzo1970]

The senders come with either the orange crap or teflon tape on them already.

I assumed if that was an issue, they wouldn't do that.

-Gonz

 

[pontiacgp]

I've used teflon tape for years on temp senders and never had an issue. The tips of the threads cut right through the tape providing ground to the sender.

I suppose if you screwed a sender in finger right you would not have an adequate ground......but that would be the least of your worries because you would have coolant leaking everywhere.

Senders have a pipe thread so no teflon tape is required. Do you use teflon tape on your brake fittings as well?

 

[87National]

Senders have a pipe thread so no teflon tape is required. Do you use teflon tape on your brake fittings as well?

Of course not.

My point was that the sender threads will cut through the tape providing a ground for the sender........if you don't believe me, try it yourself.......done it countless times over the years....temp gauge always worked just fine.