Temperature Sending Unit Compatability

[Moparfiend]

Hi, With my MOPAR high rise manifold I only have a 1/8-NPT water jacket hole for a temp sending unit. I want to use my stock dash gauge for this and was wondering what options of sending unit would be compatible with my 1970 Sat.

I would assume senders have differing resistance start and end points for the range of testing.

 

[khryslerkid]

Doesn't your sending unit go in the water pump?

For starters, one for a light are different resistance than the one for a guage.

 

[Moparfiend]

I don’t see any places for a sensor on this pump. I am not talking a dummy light sensor but the sensor for the actual factory gauge on the dash.

 

[steve340]

You would need to use your OE sender or a direct replacement for the stock dash gauge to read correctly.
Year One sells one for around $15.
I have used these a few times and they work correctly.

 

[khryslerkid]

You must have the 318

 

[Moparfiend]

You must have the 318

340 and I just determined that the aftermarket MOPAR high rise uses the same 1/8 25 NPT as the stock manifold! So I am set!!

 

[Moparfiend]

Does anyone know the approximate resistance of the single terminal temperature sender at 70F? This is the sender to the gauge not the dummy light.

Thanks!

 

[Moparfiend]

Ok after measuring a few units I found one that works. The Autozone part was 2.5 Ohms at room temp. Way too low. The Autometer was 2K Ohms way too high! The Oreily’s was 150Ohms at room temp. That close to the nominal value of 75 Ohms at room that others have measured. So I mapped it out in a pot of water with an ohm meter and digital thermometer. The curve looked right so I installed it! It works like a champ. Straight up at nominal operating temp! I will post the curve for others tomorrow.

 

[Moparfiend]

Here is the curve I promised: After looking at the curve the very hot readings may not register well on the stock meter as there is not a lot of resistance change as it gets so hot. This is typical for a Thermister. Then again the stock meter was probably never all that accurate. Just a bit better than a dummy light? I will buy an Auto-meter Gauge to supplement the stock meter as living in AZ the thermal loads are very high. I am by the way running an aluminum radiator with duel fan shroud set to 150F. Sender is part number TS17 over at Oreillys

 

[72RoadrunnerGTX]

Factory specs, all factory gauges use the same resistance to gauge sweep ratio.

 

[Moparfiend]

Factory specs, all factory gauges use the same resistance to gauge sweep ratio.
View attachment 753221

Thanks 72RR the resistance values written in are close to my research numbers and close to my curve. I do believe..

 

[Moparfiend]

I have had a few questions regard exactly which sender this is from Oreillys. They have several that are 1/8 NPT-27 . The part number is TS17 and its was $14.99