49 minutes ago, 72 Datsun 240z said:

Gauge needle moved all the way to the right till 250F when doing this test. What next?? I need a high quality japanese made sensor. Maybe nissan made in Japan.

buy this and you're done: https://zcardepot.com/products/coolant-temperature-sensor-for-gauge-japan-240z-260z-280z#:~:text=$11.99,operates%20the%20coolant%20temperature%20gauge

the end - I won’t be responding anymore since you now have the answer and a link to the part you need to fix the issue. Good luck

Edited April 26Apr 26 by chaseincats

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Edited April 26Apr 26 by Yarb
Done

4 hours ago, chaseincats said:

buy this and you're done: https://zcardepot.com/products/coolant-temperature-sensor-for-gauge-japan-240z-260z-280z#:~:text=$11.99,operates%20the%20coolant%20temperature%20gauge

the end

Thans so much!

5 hours ago, chaseincats said:

buy this and you're done: https://zcardepot.com/products/coolant-temperature-sensor-for-gauge-japan-240z-260z-280z#:~:text=$11.99,operates%20the%20coolant%20temperature%20gauge

the end

Thanks for your response and support as always

14 minutes ago, Yarb said:

Your playing right into his hand. The guy is an idiot

Who is an idiot? Im grateful for your help also!

15 hours ago, chaseincats said:

Ok, thanks for doing the test, now I'll move on - funny how you get a solution when you listen to us, huh.

Your ENORMOUSLY patient... AND FUNNY !!! 🤣

I gave up YEARS ago... But applaus, you finally got him so far to listen! (and act!) Hats off to you!!

At the end i still need to find an OEM water temp sensor made in Japan so i can get the correct temp reading!

On 4/25/2026 at 11:26 AM, chaseincats said:

Ok, thanks for doing the test, now I'll move on - funny how you get a solution when you listen to us, huh.

You have 1 test left - this will tell you if its the sensor OR the gauge that need to be replaced.

Unplug that yellow wire you took a picture of and ground it against the engine block using an alligator clip/piece of wire/whatever. Touch one end of the alligator clip to the engine block (or any groundable area), touch the other end of the alligator clip to the yellow wire's metal connector, turn the ignition key to 'on', and look at the gauge:

• IF your gauge is good, the gauge's needle will move all the way right (250+). If that happens, your gauge is good, and your temp sensor needs to be replaced.

• If the gauge does NOT move all the way to the right it is probably your gauge. Replace the temp sender too though.

This is the final test - it WILL give you a final answer.

I replaced the sender and it now sits in the middle. However it seems to be leaking coolant. Tiny drops. Im really afraid of breaking the base if i overtighten the nut. Any recommendations? Permatex?

Yes, thread sealant

What about pipe dope or Teflon tape?

Okay but using teflon wouldnt affect the reading? I can try and give it a little bit more turn but im afraid of breaking the housing.

3 minutes ago, 72 Datsun 240z said:

Okay but using teflon wouldnt affect the reading? I can try and give it a little bit more turn but im afraid of breaking the housing.

Use the thread sealant you found that @Patcon agreed you use. No more questions - you have the information you need. Do the thread sealant.

19 minutes ago, w3wilkes said:

What about pipe dope or Teflon tape?

he has a very hard time following directions - please don't throw any additional options his way