Coolant Temperature sensor

[Old60Driver]

A while back, I was trying to get my temp gauge working quickly (trying to get her back home), but wasn't having any luck, so I installed a cheapo aftermarket kit from the local parts store, and all was good (other than her getting hot on the highway when I run the A/C). Now that I've got a few hours to tinker, I'm going back down the path of getting gauges working again.

The sensor that came out looks to be a 1/2" npt, with what I would call a button type of connector. When I went to the LPS, all they had was the sideways spade type, so I ordered what I thought was the right sensor, a G1852. It LOOKS like the one I've pulled out, but it's got a larger diameter thread, and the sensor itself is larger in diameter as well (going to post a pic here in a sec).

I don't recall if there was an adapter in there, but it doesn't make sense that there would be.

Should I just go back and grab the smaller sensor that they have in stock and modify the connector to fit or keep trying to find the right one? I worry about the ohms of resistance in something other than factory stuff...

Thanks!

 

[45tt]

I’d say go back and get the correct ACDelco part for your truck. I tried an aftermarket temp sensor and my temp gauge would peg out to the max hot immediately at startup even when the truck was cold. I believe the problem was the new aftermarket temp sensor was a different amperage. I had to order the correct one through autozone and wait a few days to get it.

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[75gmck25]

GM made temp sensor matching difficult, since the sensors and resistance changed over the years. For example, the sensor in my ‘75 would never make an 80’s gauge read correctly.

Correct sensors for the later trucks are usually easier to find, but not all parts references agree.. I would compare RockAuto, Autozone and other sources to see what they recommend, and pick the most common part listing, Also check pictures to see which one has the button connection you need to match your wiring. Some of the parts books are just flat out wrong!

 

[AuroraGirl]

COOLANT TEMPERATURE GAUGE PARAMETERS

For Truck Years: 1967 - 1973
The Temp Gauge Needle Should Point to:
Left Line (Cold) when sender resistance = 350 Ω
Middle Line when sender resistance = 76 Ω
Right Line (Hot) when sender resistance = 51 Ω

For Truck Years: 1974 - 1978
The Temp Gauge Needle Should Point to:
Left Line (Cold) when sender resistance = 350 Ω
Middle Line when sender resistance = 68 Ω
Right Line (Hot) when sender resistance = 46 Ω

For Truck Years: 1979 - 1990
The Temp Gauge Needle Should Point to:
Left Line (Cold) when sender resistance = 1,365 Ω
Middle Line when sender resistance = 96 Ω
Right Line (Hot) when sender resistance = 55 Ω

as you can see there are three different ohm ranges depending on the year. there are also 1/2" and 3/8" pipe threads so you need to match the size.

thanks c10 maybe this will help this guy
source:

Single wire temperature sensor versus two wire sensor

I bought a new coolant temp sensor (it is a two wire connector) and went to put it in and realized the sensor in the truck only had one wire. If I use the new sensor which wire do I use and what happens to the other wire. Should I just take it back and try to find a one wire sensor?

www.gmsquarebody.com

 

[AuroraGirl]

You must be registered for see images attach

Temperature Sending Unit

Temperature Sending Unit

www.americanautowire.com

"The correct GM part for 1973-1978 C/K (all styles, all engines) with gauges is GM #1513321" is what that product is for


dont take my word for it but this appears to be what you are supposed to have:

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http://forum.73-87chevytrucks.com/smforum/index.php?topic=32806.0 here is some reading, I now second guess myself lol

 

[Turbo4whl]

Some factory wiring temp connectors would fit both types of sensors. Slide on sideways for the nail head connector or push straight on for the spade connector.

@Nasty-LSX

Looks like you and Nasty need to swap parts:

Pipe thread change in the head

 

[Frankenchevy]

The sensor that came out looks to be a 1/2" npt

I believe that smaller one is actually 3/8NPT

 

[Old60Driver]

I believe that smaller one is actually 3/8NPT

You're right. My brain farted...

 

[Old60Driver]

I’d say go back and get the correct ACDelco part for your truck. I tried an aftermarket temp sensor and my temp gauge would peg out to the max hot immediately at startup even when the truck was cold. I believe the problem was the new aftermarket temp sensor was a different amperage. I had to order the correct one through autozone and wait a few days to get it.

You must be registered for see images attach

That's exactly what I bought, but it's too large. Won't fit in the coolant hole.

 

[Rusty Nail]

Wont fit?

Add lube.
Get a bigger hammer.


Don't wurry - itll fit BB


Listen to gmck25 up there.
There are possibilities...it is imperative to run the correct sensor.

All that stuff changed over around 80-81 (to run computers) and AGAIN in 86-87 to switch to metric/centerbolt valve covers - noting the death of the Quadrajet in 87 and introduction of stricter emmision controls to mark the start of the '80s.
Coolant sensors AND oil pressure sensors could differentiate , 40 years later - be aware.

I sure as hell would try to NOT modify the wiring.

Hope this helps!

 

[75gmck25]

Auroragirl's post is a very good example of how confusing the temp sensor search can become. She posted a picture that has a blade connection, but if you run a Google search you will find that the GM #1513321 sensor has a button connection.

The GM #1513321 sensor is correct for 73-78 trucks, but if you try to find one it is usually out of stock or they want an atrocious price for it because Delco no longer produces them. After a lot of online searching and matching I determined that the Standard Motor Products TS6 will work for the 73-78 trucks, and its available from several sources (I think I got mine at Autozone). However, the OP has an '84 truck, so it needs a different sensor.

I am using a TS6 in my '75, and I also have a mechanical temp gauge under the dash. With the temp needle on the stock dash gauge about halfway between the 1/4 scale and half scale marks (there are no numbers), the separate mechanical gauge shows about 185. As the engine warms up I can watch the needle go up to just over half scale (about 195 on the mechanical), then see the thermostat open, and it drops down to 185. That setup works for me.

 

[AuroraGirl]

Auroragirl's post is a very good example of how confusing the temp sensor search can become. She posted a picture that has a blade connection, but if you run a Google search you will find that the GM #1513321 sensor has a button connection.

The GM #1513321 sensor is correct for 73-78 trucks, but if you try to find one it is usually out of stock or they want an atrocious price for it because Delco no longer produces them. After a lot of online searching and matching I determined that the Standard Motor Products TS6 will work for the 73-78 trucks, and its available from several sources (I think I got mine at Autozone). However, the OP has an '84 truck, so it needs a different sensor.

I am using a TS6 in my '75, and I also have a mechanical temp gauge under the dash. With the temp needle on the stock dash gauge about halfway between the 1/4 scale and half scale marks (there are no numbers), the separate mechanical gauge shows about 185. As the engine warms up I can watch the needle go up to just over half scale (about 195 on the mechanical), then see the thermostat open, and it drops down to 185. That setup works for me.

Id say. it went good until it didnt.

 

[Old60Driver]

Auroragirl's post is a very good example of how confusing the temp sensor search can become. She posted a picture that has a blade connection, but if you run a Google search you will find that the GM #1513321 sensor has a button connection.

The GM #1513321 sensor is correct for 73-78 trucks, but if you try to find one it is usually out of stock or they want an atrocious price for it because Delco no longer produces them. After a lot of online searching and matching I determined that the Standard Motor Products TS6 will work for the 73-78 trucks, and its available from several sources (I think I got mine at Autozone). However, the OP has an '84 truck, so it needs a different sensor.

I am using a TS6 in my '75, and I also have a mechanical temp gauge under the dash. With the temp needle on the stock dash gauge about halfway between the 1/4 scale and half scale marks (there are no numbers), the separate mechanical gauge shows about 185. As the engine warms up I can watch the needle go up to just over half scale (about 195 on the mechanical), then see the thermostat open, and it drops down to 185. That setup works for me.

Okay, that makes a lot more sense now. I obviously couldn't install the larger sensor, so I found the one shown below at the local parts house. I was trying to test it with boiling water and see how it would change the resistance. Never changed a lick. The sensor showed open the entire time. Next test will be to wire wrap the threads and connect it to ground, connect the spade connector, and place the sensor in boiling-ish water. See what I get (if anything), and compare it to the aftermarket gauge I have installed.

Thoughts?