temp sensor question

[mbaird]

This is a curiosity question.
Is the temp sensor for cars with dummy lights a switch or a potentiometer ? If it is a switch what degree is it set to turn the light on ?

 

[Dana67Dart]

With light it would be a switch. Best guess 220-240 or there abouts.

 

[4spdragtop]

I would think potentiometer. It has a "range" I believe as opposed to switch. But I'm guessing lol

 

[mbaird]

wow 220 seems pretty hot before it notifies you of overheating.

I was just bored and curious to know if you could use one to activate fans or such...

 

[AJ/FormS]

The Blue-Streak catalog used to have a couple of pages of them, including specs and thread sizes and such.
You can test them by putting them in oil and slowly bringing the temp up. Engine oils typically don't boil until past something like 250. With a voltmeter attached, it will flip from infinite resistance to zero resistance, at the switch-point.

My Standard Catalog lists several Mopar switches that flip at 220*F.

 

[mbaird]

Service manual didnt have any reference to them . Not even diagnosis..

 

[AJ/FormS]

info added to post #5
My Standard Catalog lists several old-style Mopar switches that flip at 220*F.
But the tolerances run generally from 5% to 12%, which translates to 11* to 26* ouch, choose carefully.

 

[mbaird]

info added to post #5
My Standard Catalog lists several old-style Mopar switches that flip at 220*F.

interesting... I would not have guessed it would be that high.

I guess we may be over reacting when we panic about our engines hitting 210-220 range.

 

[67Dart273]

Those sensors are a thermistor. "Somewhere" there is a chart of temp vs resistance

Here is a random one I found just as an example

http://pe-ltd.com/assets/coolant_temp.pdf

 

[AJ/FormS]

I run at a minimum 205

 

[72bluNblu]

interesting... I would not have guessed it would be that high.

I guess we may be over reacting when we panic about our engines hitting 210-220 range.

Yes. 220 shouldn't be boiling. Remember water only boils at 212*F if it's not under pressure. At 16 psi even just straight water doesn't boil until its 252*F. And that's still straight water, depending on the coolant mix it can be higher than that.

Now granted your gauge only shows the temperature in one spot and it may not be the hottest place, but I don't worry too much unless I've gone past 220 and am on the way to 230+. My car seems to run best when it's around 200-205.