1982 720 Coolant Temperature Sensor Replacement

[720_Daniel]

Hi good folks. I can't find a suitable replacement for my temp sensor. 

My guess is that these things function pretty similarly across the years. Is there a part with the same threads that anyone else has had luck with? M14 threads I think. 

 

[datzenmike]

What is your exact build date on the door jam?

 

You have a Z24 engine?

[720_Daniel]

Door jamb says 5/82. 

Engine is z24. 

[datzenmike]

That's an '82 model year and would have a Z22 in it. Check engine tag on right inner fender under the hood hinge, should say Z22 under engine. Prior to 11 '82 that water temperature sensor wasn't used. The transplanted Z24 engine came with a later ECC feedback carburetor and does need the input from the sensor to run properly. Does it run poorly and get really bad mileage???

 

Maybe the door was changed

[720_Daniel]

I should've mentioned. It's a CA emission special. I got the z24 info off the engine block. My main trouble at the moment is passing smog. I think this is part of the problem. 

 

[datzenmike]

Does the engine plate on the passenger inner fender say Z22???? If it does then the Z24 engine was transplanted and will have to pass the Z24 emissions, what ever they are.

[Thomas Perkins]

I have a z24 engine and this is what I use.Long ago when Fred Flintstone was still on t.v.My temp. sensor connectors dry rotted so I bought this,has a lifetime warranty.https://www.autozone.com/engine-management/coolant-temperature-sensor/p/duralast-gold-coolant-temperature-sensor-su405dg/625842_0_0

[720_Daniel]

Oh man. You're totally right. What a story this truck must have to tell. I probably need to go back to my original idea and convert to electric. 

[720_Daniel]

Thanks Thomas Perkins. Unfortunately, my sensor is smaller, the threads are fine, and the diameter of the opening is wider. 

I did the fun thing and pulled the sensor apart so I could see what made it tick. It had some resin embedded components. There's a flat disc that lays against the brass on the coolant side. Then there is a funny shaped piece of metal that has contacts on either side. I think the disc must expand with heat and drop the resistance by increasing the contact points of the two metal parts. I was hoping to find a similar sensor and pull it apart. Then epoxy the bits in. 

[Thomas Perkins]

Here it is,look at the price.It fits the 82 Nissan 720,82 Nissan Stanza,82 Nissan 210.Check out this other site.Which is cheaper.https://www.autozone.com/engine-management/coolant-temperature-sensor/p/duralast-coolant-temperature-sensor-su7393/857133_0_0.....https://www.finditparts.com/products/2510589/standard-ignition-tx93

Edited November 12, 2022 by Thomas Perkins

[datzenmike]

The Z22 had a regular carburetor. In 11 '82 at the start of the '83 model year the 720 switched to the Z224 engine. California emissions 720s had an ECC (electronic controlled carburetor) that had a solenoid primary jet that was turned on an off many times a second that adjusted the jet open time to maintain a stoichiometric air fuel mixture with feedback from the O² sensor in the exhaust and a few other things. Your '82 won't have the wiring or the ECU box under the driver's seat to make this work.

 

If you can find an Z22 carburetor and throw it on, and if the inspectors don't notice the Z24 on the block it might pass the visual inspection. I guess remove the O² sensor and plug the hole.  

 

 

[Thomas Perkins]

Just found this Nissan site.With the Nissan part number.Click on what this fits. You might have a different intake on that Z24 engine.https://parts.nissanusa.com/p/89490588/2212023M00.html

Edited November 13, 2022 by Thomas Perkins

[720_Daniel]

Welp. That was a journey. I ended up going through a few wrong parts and finally just made something work.

 

Here is the correct part for my Z24 in a Z22 truck ( I think).

TS-142 which fits a 1983 Nissan Stanza. 

https://www.ebay.com/itm/163458794569?epid=77012675&hash=item260ee74449:g:X3wAAOSwZBRcKMqR

 

Here is the part I bought using the image as a guide for my guess. It did not fit. The TS-493 fits a Nissan 310.

https://www.ebay.com/itm/255651677507?hash=item3b86070543:g:0hoAAOSwlQ1h2BfB

 

So did I go and buy the correct part? Nope. I left a puzzle for the next owner to laugh at. 

I had drilled out the guts from the previous temp sensor. The inside of the nut is sealed off to the engine, so there's no risk of leakage. But, there is a recessed area that is conveniently the right diameter of the Nissan 310 temp sensor that I bought incorrectly. So, I used the high-heat JB weld and screwed the 310 sensor in place then screwed the whole assembly in. 

Voila - temp gauge works again. 

 

 

[datzenmike]

You have the round 6 wire plug at the back of the carburetor?